My main pet peeves are crude traits in people, you know, like sneezing in your hands, chewing with your mouth open, chewing on your fingernails, etc. I can't stand those type of things and I hate to see people doing them.
One of my main MINECRAFT pet peeves is when people leave floating trees. I mean, I can understand it if it's by mistake, because you don't notice a block you left hiding in the leaves of a big tree or something. But, most people who do it leave wood in the tree deliberately and they just leave a mess of floating bushes in the air.
Some of my other Minecraft pet peeves are people who don't read the chat, people who fail to have common sense in figuring things out on their own (i.e. not being able to think to use the google search engine or youtube to find out how to install a mod or something) and people who get stupid skins (like teen hoodies) or people who don't organize their inventories. One last one is people who don't know how to properly survive, like they come onto a server expecting a kit to start off their survival, and if there isn't one they'll say, "HOW DO YOU EXPECT ME TO SURVIVE WITHOUT A KIT?!????!???? <----Oh, and this sparks another one. People who use excessive and unnecessary exclamation points and question marks.
Sorry, this kind of turned into a rant. I might actually turn this into a blog now that I think about it