Worst thing a cosplayer, or just about anybody, can do:
Getting really far ahead of your own skill with your ego, bragging rights and a reputation are earned and not claimed. I mean really, who wants to be 'oh him/her, such an ego maniac."

>What's the worst thing a cosplayer can do?

Seriously?
Cosplay.
It is a horrible hobby and you should feel ashamed for participating in such a hobby.

Piss on the stage in a Kamehameha contest

Cosplay as someone they really, really don't suit well. whether it's looking too old for a 14-year-old girl or looking too young for a 40 year-old guy, being way too fat, too way short for a character that's 6', too flatchested for a character with exposed cleavage and H-cups, being too fucking UGLY for a gorgeous girl, whatever. Choose a fucking character you can pull off.

Treating people who are new to the hobby like shit. If you don't like someone's cosplay, just keep it to yourself and try to remember that you were probably a shitty weaboo "cosplayer" at some time, too.

Post on /cgl/

I don't mind OC at all if the cosplay looks nice. 12-year olds are about the last people who should do OC since they couldn't do a decent character design even if their life depended on it.

>>4595095
I think cosplaying an OC could be a good creative exercise. Two things, though:
1. Make it truly original, having nothing to do with any existing thing outside of your imagination. For instance, don't make a Naruto OC.
2. It might be better used in live-action role-playing, as opposed to attending a con dressed as it.

What's the worst thing a cosplayer can do?
Same as anybody else: being a dick.

>>4595324
Quit being a jerk. Kids dressing up as characters they make up is cute.

Also, a lot of anime character design is lame. Like, a big chunk of it.

Be rude and start drama, or be impolite, especially to newfags who don't know any better.
Ruining everyone else's con experience is never okay. Not if you think they are ugly, not if your cosplay is better. They are still human beings and don't deserve that shit.

Also, trying to claim someone else's work as your own.

>>4595365
Or straight-up generic. Seriously, with so much anime these days, it's like "Gee, where have I seen this school uniform/hair color/eye design/way-bustier-than-a-schoolgirl-should-be design, etc." Especially the eyes. Jesus, guys, learn to draw some fucking eyes that don't look like everybody else's eyes.

Sage for off-topic bitching.

>>4595359
Yeah, I met a girl who was doing this at a con recently. She was an OC from a book she's writing. It was very cool and she put a lot of work into her costumes, poses, etc.

I also love steampunk for this reason when it's well done. There are some groups in my area who do steampunk larp-things or dress as OCs from a steampunk world, and they are very cool.