People who misunderstand and put something very different into what you said than what you meant, and then keeps on misunderstanding and get upset when you try to explain, and maybe even say that wasn't what you originally said, just because they interpreted it differently
People who repeatedly ask for your opinion, which you are reluctant to give because you think you know how they will react and lo and behold, they have the exact reaction you assumed. (And then you are against them of course, just because you happen to disagree and are honest yet as understanding as you can be in your feedback)
People who expect you to be a mind reader, even when they say the exact opposite of what they mean.
People who litter
People who use grills during droughts when they are forbidden. They're more than annoying though, as they potentially put people, animals and nature at risk