I hate when a response doesn't contribute anything.
For example, there was a question along the lines of "For people who wear glasses, are they hard to get used to?" And someone answered "I don't wear glasses". Then don't answer the f*cking question. Haha that just annoys me.
Lackluster unimaginitive answers. If I ask: Who is your same sex crush and you say I don't know or even worse I can't think of one after I said playfully Oh come on any one. Those are not the answers that I yearn for or am fond of...
The ones that don't answer your question. For instance, on my Harry Potter question, I don't want someone to answer if they are not really answering the question. Or when I asked about the candidates for the Republican Party. I gave specific instruction. If you don't want to answer it, don't. Quit shopping for points.
Disrespectful and annoying people, They are just really annoying. I have asked questions before in the past and there was this girl who kept answering on my questions and wasn't really giving any answers except just trying to get my attention. Its not once, but like a few times I have asked questions, she doesn't do it anymore but still it was annoying as hell.
I dislike stupidity and banality without any humour. Prejudices are also unpleasant and if an user gives very simple answers by a complex topic, like it do for instance easy riders and such without sense and mind. Answers of nationalists, racists and other philistines can be unpleasant too.