I don't know how to describe it, so I'll give an example.
When I was in grade 9 there was this kid who would annoy the hell out of me when I worked with him. We had to make a very healthy one day diet. He's like "Let's add cookies!" and I was like "They're not healthly though, this is supposed to be a completely healthly diet" and he's like "Who cares, just add it!" and he pretty much kept argueing. His main arguement would always be "Who cares!". It pissed me off like crazy, we could easily improve our mark by doing little things but he wouldn't let me and just go "Who cares!!!". He wasn't the type of guy who got bad marks either.
Another thing from school that bugged me was group projects. Most kids would copy and paste as most teachers didn't care about sources which pissed me off. I'm stuck in a group with a bunch of *******s who copy and pasted a paragraph from the web (usually I can recognize where they copied it from as I visited the site while reasearching!) while I wrote about 10 pages. Then there's this one ******* who also didn't do anything who I let read a bunch of things as it was an oral presentation. He sucked so badly, he skipped words, misplaced words, stuttered to the point where it was hardly recognizable and it made no sense.
Now that I think about it, these aren't actually little things, more like medium sized things from the past. Oh well, I already wrote it out. Here's a small thing that pisses me off though, people who post pictures on places like Myspace or Facebook where they say in the description or whatever "Eeew, I look so ugly in this picture!" if you look so ugly, why upload it?