1. I dislike fics in which Harry places his trust with the Goblins blindly. In the actual books I felt Harry was too trusting of most people including Dumbledore. While a certain amount of trust has to be given to everyone, for example trust that people preparing food are doing so properly, I am a believer that trust should be earned. Part of the reason I like the Harry/Hermione pairing is because she is really the only person who in my opinion has earned Harry's trust with Ron the second most trust worthy. They earned Harry's trust though Ron less so than Hermione. Harry trusting the Goblins with basically everything is very annoying.
2. Beyond the easily ignorable (because it occurred in one of the books I didn't find to be very good) betrayal by Griphook (because he wanted the sword and all goblin made items forever belong to the goblins) I don't really get fics in which Harry is extremely wealthy and decides to have Griphook manage his accounts. Just because he's the only Goblin whose name Harry knows doesn't mean a thing. Griphook was a clerk, I'd prefer someone with experience and knowledge to manage my accounts, especially if they are large.
3. The Goblin bank is often portrayed like a modern western style bank and government office (will readings, Realtor services, and lawyers can be found there in some fics for some reason). The actual books portray them more like an old style or some Muslim banks in which interest is not earned you have to pay for storage more like large Safety Deposit Boxes. Not every bank gives interest and some have very poor interest take Japan for example where it fluctuates but has generally been a negative interest (i.e. you pay them to store your money).
4. I find it very annoying for characters to constantly say things like Merlin this or Merlin that. It is especially annoying when done by muggle-born.
5. As I mentioned in an earlier post the way money is displayed is very annoying. How does Olivander make a living? The ingredients used, like unicorn hair said by Slughorn to be 10 galleons a hair, cost more than the wands he sells. Why is pretty much everything listed in galleons with very little mention of sickles or knuts (even more so in fan fics)?
6. I quoted Hermione about wizards not having logic and that remains a constant (as in it is basically the only legitimate excuse for some actions). Why did Dumbledore send the students back to their dormitories in book one when the troll was spotted? Wouldn't it have been safer to keep them all in the great hall where all the teachers can be around to watch them and not send any student toward the dungeons which is where the Troll was said to have been and is the place that some students like the Slytherins have their house?
7. Why is it that basically everyone seemed to know where Harry Potter lived? I mean the address was said during the court case, owls about misuse of magic where able to get to him, could be followed from the train station, house elf i.e. Dobby had no trouble finding him, the entire order of the phoenix knew where he was, a temporary flue connection was made to the house at one point, people would randomly show up and shake his hand pre-first book (mentioned in first book), etc. Whatever protections that were put on that house were crap the only reason Voldemort or the death eaters didn't kill him seems to be massive incompetence. Catching Harry outside those protections shouldn't have been hard at all. Yes Voldemort states, in the Goblet of Fire, that Dumbledore placed an ancient magic, to ensure the boy's protection as long as he is in his relations' care but really that didn't stop an elf nor does it stop muggles like say Petunia who was going to hit him with a frying pan (second book that occurred and they could be cursed via the mind control curse to kill him) or stop Dementors from attacking him nearby. Even if the protections worked to stop Voldemort, which I'll go ahead and say is true since he was defeated by Harry just touching him in the first year, why have Harry still go there after Voldemort used Harry's blood in the resurrection ritual? With them both having the same blood Voldemort should have been able to waltz right into the house and kill Harry in his sleep (which is another thing I didn't get why didn't Voldemort ever try and kill Harry in his sleep when he had the chance?).
8. Fics in which Harry or Hermione trust and can rely on Minerva McGonagall annoy me. She didn't approve of the Dursleys but she also didn't do anything like check up on Harry ever. She sent first year students to the forbidden forest for detention when it was known that something fast was killing Unicorns in the forest. She didn't help with Umbridge or when they went to her with concerns about the Philosophers stone. She didn't stand up for them when the Potter stinks badges where being passed out, Heir of Slytherin thing was going on, do anything about Snape's blatant favoritism, or do anything about Draco verbally abusing students even in the great hall (she should have taken points or gave detention or something - and about that why did she take so many points away from Harry and Hermione in the first book prior to giving them detention in the forest others did not lose as many points for breaking curfew). She didn't try to help during the Tri-wizard tournament. She like Dumbledore did not seem to check new hires credentials. I wouldn't even go to her for advice since the advice she did give was useless.
9. Should what happened in the books be used in a fic or should it be made to more resemble real life when possible? For example in the books Hedwig hoots but in real life Snow Owls are diurnal and silent they don't hoot (they do make a barking noise on occasion though). Another example Harry holds his breath while ascending during the second task. In real life that shouldn't be done. Instead he should exhale as he goes up to prevent lung damage.
10. There were a number of things that bothered me in the Goblet of Fire but what annoyed me the most was that Ron Weasley was Harry's hostage during the second task. I find myself very annoyed about how Harry (and even more so Ron) tended to treat Hermione (she was a much better friend to them than they were to her). The way I see it Hermione was a true friend of Harry's the type that he could trust, could be counted on, and would do what she believes is in his best interest even if it was detrimental to her. Ron was not that type of friend. He was a buddy who was fun to hang out and do stuff with like talk about sports, play games with, and just goof off with in general. Krum didn't really know her enough to be his hostage and Harry still should have been some what pissed at Ron (I really didn't like how quick he was to forgive Ron's betrayal - should have made Ron work for it some or at the very least hit Ron a few times before accepting it).
11. Ron Weasley. I don't much like this character. He is basically a normal kid (at least compared to Hermione and Harry) lazy, antagonistic, prejudiced, a jerk, tends to be jealous/envious of others, somewhat of a mommas boy, has an inferiority complex about his brothers as well as Harry, and seeks attention. Ron really is not very different from Draco (he was pretty bigoted and cruel on occasion, he caused Hermione more pain than Draco ever did, there are more similarities as well). He had a real purpose early in the books but not so much later (in that his role was not really vital). I did sort of feel sorry for him on occasion like having to work with a broken wand, being poor, being overshadowed by his other family members, etc. but I can't really relate with him though I probably should be able to more than I do.
12. Ron had to use a family members old wand and couldn't get a new wand quickly because his family is poor and he didn't think of/strangely too proud to just ask Harry to loan or give him the money for one. A wand is the single most important thing a wizard will ever have. If the Weasley's had trouble affording one what do poor muggle-born students do (like say the working homeless)?
13. Why didn't Harry or the others carry things like a bezoar (stone from the stomach of a goat that will save you from most poisons)? With someone actively trying to kill him you'd think some preventive measures could have been put in place.
14. Hermione Granger is my favorite character in the series and the one I can most easily relate to. The things I liked most about her was her loyalty and social conscience (which caused her to create S.P.E.W for the elves, try and prepare a defense for Buckbeak, and taking Crookshanks because no one wanted him). Though I dislike some aspects of her character such as how she trusted authority figures too much, wasn't as open minded as I would like, and her pushiness. I found myself sympathizing with and feeling sorry for her when I read the books. Harry had a pretty crappy life but I did not find myself sympathizing with him as much as Hermione for several reasons but I think the main reasons were because he was too much of a sycophant to Dumbledore, he sought out the trouble he encountered fairly often, he kept trying to take on wizards far older and far more experienced than him with no plans in place and fairly poor tactics, he didn't try and improve himself so as to better himself or just increase his chances of survival unless forced, and tended to blame Draco Malfoy for everything (to the point when it was actually Draco no one really wanted to believe him anymore).
15. The use of glamour charms and disguise magic is common in fan fics but doesn't seem to exist in the actual books beyond polyjuice potion. They never use any type of glamour magic and when disguised it is either via polyjuice or just dressing up (the wizards are not good at disguising as muggles). When Hermione tried to disguise Harry from the snatchers she covered Harry's face with welt rather than use any type of illusion and she out of anyone would have learned at least some basic ones had they existed. That said I believe it is shown at least once in the movies.
16. Reading the books I always felt that Hermione was more powerful and extremely more skilled than Harry (and that in the last books in particular she was nerfed to not overshadow Harry). She was smarter, shown to do spells from different years, learn spells faster than other students (on her first try often), very good at nonverbal spells (better than the vast majority of the characters), altered spells and was implied to create her own spells (the point me spell for example), was shown to practice at wandless magic (by jumping out of trees and slowing her decent wandlessly in the books, in the movies she is shown to do a few spells like the confoundus charm wandlessly), etc. Harry was not powerful or very skilled he was barely above average. I don't even see him as being more skilled than Hermione in defense against dark arts. He got special tutoring in that (Lupin, Snape -though learning to protect his mind didn't seem to really work well, and later Dumbledore but that mostly consisted of watching the equivalent to home movies on Voldemort) and preferential treatment because of who he was. Part of Harry's power may have not been his alone rather been Voldemort's since he was carrying part of Voldemort's soul and it did give him abilities such as the ability to speak snake. Hermione even taught him quite a few of them (for example in preparation for the tasks in the tri-wizard tournament and for the DA). Harry did not win his battles because of skill or power. Frankly Harry's tactics and strategy were atrocious. Harry should have been dead the only reason he survived at all is because luck, over confident and incompetent enemies, objects that show up exactly when he needed them, near dues ex machina things happening, help from others such as Dobby, Moaning Mrytle, Hermione, etc. The thing I really, really dislike about powerful, skilled, independent Harry fics (which are better than what he was in the books IMO) is that they tend to really nerf Hermione.
17. While I prefer Harry/Hermione to what was in the books (I really hate Ron/Hermione). I don't really like the book version of Harry all that much and feel that while better than Hermione/Ron it still is not a great match up. The reason for that is because Harry was not much better to Hermione than Ron was. He was a jerk that made her cry as well (like at the beginning of the fifth book). Blamed her when he really shouldn't have. Didn't stand up for her when he had the opportunity to as often as he should have and tended to side with Ron over her (and she was a much better friend to him than Ron was). Didn't really acknowledge Hermione's help didn't ever really thank her or apologize for hurting her (when she was crying in that stupid tent he could have at least tried to comfort her instead of ignoring her and being mad at her for accidentally breaking his wand while saving his life). He didn't really help her with things like SPEW unless forced by her to do so. Both Harry and Ron had fairly one-sided friendships with Hermione where they tended to use her (for example in the beginning of Deathly Hallows he thinks about how he should get Hermione to teach him some healing spells - he doesn't seem to ever think about ways he could help her). She tried to better them and help them all the time (even breaking rules and endangering herself for them) they didn't really do that for her very much.
18. Loyalty oaths (like the unbreakable one Snape made), Veritas serum, Magical contracts (like the one Hermione created or the goblet), etc. were underused and could have been extremely helpful. The order of the phoenix should have used those things.
19. I really don't like how Hermione cried so often. She was strong, independent (the most out of anyone in the series), brave, outspoken about her beliefs at one moment and then crying the next. I really don't get why the author had it that way. I don't even really get why she was crying on some occasions since by that point she really had no reason to cry.