Having recently gotten back into Percy Jackson fanfiction, I can now claim my least favorite Percy mischaracterization that I am seeing all the time:
He is not cheerful.
If the first thing you're having Percy do when he meets a new person is start grinning and joking around, you have fundamentally misunderstood him. He is quiet, surly, has the look of a troublemaker, and if he's smiling at you, it's because a) he likes you and thinks of you as a friend or b) he is acting, probably to trick you into fucking up so he can fuck you up.
Nearly all of his commentary should be internal. He's a funny guy (in his thoughts) but he doesn't say much.
He's also fundamentally a very kind person, but he's going to express that through actions before words.
If anything, strangers looking at him should be thinking that he looks like his father: the same brooding look on his face, scowling - and then be surprised when he does something nice. He's got a serious case of resting bitch face.
And while I have your attention, here's my second least favorite Percy Jackson mischaracterization: he does not go around mouthing off to gods for no reason! Holy shit why does everyone have him doing that?!?
Yes he's stubborn and impertinent - but he's not stupid. His first approach every time when talking to a god is to think "ok Percy, how best to not make them mad at me and turn me into a horrible little insect?" The cases where he doesn't do that are outliers, even if they're memorable:
Meeting Dionysus for the first time: a) he's just found out he's a demigod and is grappling with the idea gods are even real; b) Mr. D is giving off serious alcoholic vibes that set off his childhood trauma from Gabe. And when Mr. D threatens him, he shuts up! He's more casual around Mr. D considering he's the god Percy is around the most, and even then Percy's go-to strategy with the guy is to avoid him whenever he can, and if he can't, to stay silent unless there's something really egregious that he disagrees with (example A being Tantalus.)
Meeting Ares on the lightning thief quest: Ares fucking whammied him with his rage aura, and even then Percy was doing his best to be polite while turning him down - because they were on a time sensitive quest!
Fighting Ares in LA: Ares straight up was part of the plot to frame Percy for the theft and drag him into Tartarus with the bolt. He was also preventing Percy from getting the helm and returning the bolt to Zeus - if Percy didn't fight him he was gonna die anyway, frankly from a number of options: Kronos rising, the gods going to war (and probably sniping each other's demigod children), Zeus!!!!, Ares himself to cover up his involvement, Hades!!!!, Poseidon for failing him, for all Percy knew (he'd never met the guy, and all he knew of the gods at that point was that they thought of demigods as tools in their arsenal, not children.) They were past the point of polite reconciliation by then, so Percy challenging him to a duel and luring him into the sea was his best option.
Hades: he is remarkably polite to Hades, even when he tries to imprison him in the underworld for the crime of nearly being sixteen, and Percy has to fight him to escape.
Hermes: he is also very polite to Hermes! Especially since a lot of their conversations involve Percy trying to delicately deliver harsh truths (about Luke) to the guy.
Artemis: pretty sure the only impertinent thing he does around Artemis is try to stand up for Bianca's right to choose her future, since he thinks she's being pressured into joining the hunt. And even that is just to advise her that she should find out what camp is like before swearing an eternal oath. And then when Bianca makes her decision, he shuts up and doesn't try to interfere with her life choices. He's very polite to Artemis! And also respects her a lot.
Apollo: lmao frankly Apollo is the one taking liberties in his relationship with Percy, considering they hardly even talk before Apollo shows up as a mortal during ToA (and by then Apollo has a massive hero crush on Percy, even he never says that explicitly). And even then, the pushiest Percy gets with him while Apollo is an immortal god capable of crushing him like a bug is when Apollo shows up to help with the quest to free Artemis, and that's pretty much just to ask for more information - which, I mean, is for the purposes of helping Apollo's beloved sister. Apollo would've helped more if he could've.
Poseidon: Percy is very respectful of his father, and even when Poseidon says he's his favorite son, Percy is wary of upsetting him. He's tells Poseidon his honest opinion as politely as he can, and pretty much always keeps in mind that it might get him smited - he just takes the risk because he honestly believes what he's saying is important. In any conversation they have, he lets Poseidon lead.
Zeus: Percy is afraid of Zeus, for good reason. I think he closest he comes to mouthing off is when he blurts out his impassioned argument in favor of letting Bessie live - which Zeus ultimately lets happen. Heck, I think the only person to tell Zeus he's wrong (other than Poseidon) is Jason?!? Put some respect on Jason's name. (Even if that did ultimately get him killed, imo.)
Like, I'm sure I missed some, because this is getting long - but the idea that Percy would get in a room with any immortal god and start mouthing off from the get-go is absurd. He has to be seriously pissed off to do that - and even then he's either going to a) temper what he says if he's trying to have a conversation or b) have already decided he's gotta fight his way out (see: Ares, Akhlys.) You know who is more likely to do that? ANNABETH. I love the girl but she absolutely lets her pride get in the way when she's talking to gods - to the point that more than once Percy has had to step in to try to smooth things over and cool things down. (See: Hermes, HERA)
