Wolf-speakers being let into "literate" roleplays. I immediately leave groups that allow in wolf-speakers, because I cannot roleplay with them. I know it makes them feel more literate, and I'm not going to rant, but wolf-speak is the misusing of "fancy" words to the point of being unreadable to me.
When the login page refreshes and logs you out. I have to log off the game, log into the login page, wait a minute, then get back in to avoid crashing. It's annoying because I'm always roleplaying, and I often miss a post or two. During a battle or conversation scene, this is very frustrating as I have to ask what I missed.
The eyebrows. I don't know why, but I don't like the eyebrow texture.
Default characters who have presets. Please, give us a hint to what your preset may look like.
This one is kind of nitpicky, but when people don't begin a continued role-play post with "<" or "<<". It can lead to problems when you being the next post with "/" to show thought or emphasis, and can sometimes be confusing. I don't call anyone out on it, but it is just slightly frustrating when I see someone in group chat freak out because they started their post with "/" and sent it and now it didn't show up.
People being alienated because of their unrealistic character design. I can see someone saying "Whoa, you're character design is blinding!" and not meaning to hurt anyone's feelings, but calling others "sparkle dogs/cats" can be offensive.
People that think it's okay to bang in Ficho or Bonfire. You shouldn't be doing that in the first place, but at least do it in a private map.
Unwanted group rivalries. If you're all part of one overarching role-play, it's fine to have some pack/pride/Clan/tribe rivalry, just not if everyone is separate. This mostly applies to mappless groups in Fluorite. If anyone remembers ShatteredClan, they were a wonderful example of unwanted rivalry. I remember role-playing as a kit, and ShatteredClan came and attacked us out of nowhere.
One-dimensional personalities. These are cliche characters that are lazy just because, evil just because, etc, and don't have any other personality traits. They have some cliche backstory, or the creator didn't make one at all. I have an insane character, but he's so much more than just insane; he's a protective brother, willing to die if it meant his sister would live, and that has a reason behind it. He's got the capabilities of being a devoted boyfriend, and so much more than just insane. It's the one-dimensional characters that are the way they are just because they can be, and have no reason to be, and have no quirks or other personality traits.