High school students and their valley girl talk. Makes a conversation unlistenable. "Like, you know, like?"
Again, people who don't like special interests. Mine are so small/niche that I cannot discuss them at school, because I am worried people will call me "weird," "freak," "crazy," "stupid," etc. for doing those interests. So I have to continue to use my "Safe & Sane List" of topics with NTs. Sports, school, latest news (albeit some NTs never watch news, only endless hours of "SportsCenter", ugh), movies, TV shows, etc. Special interests are a no-no and I don't discuss them. Sometimes my conversations are quite awkward because I cannot talk about my special interests without consequences.
People who stare at their phone 24/7. No reason to do that. I have a PC at home and never bring any electronic devices to school. They are not allowed ANYWAYS!
Students who still continue to whisper to their friends when the teacher is talking...or when others are taking a test and they are finished. It makes me want to stand up and scold them for what they've done.