Slow drivers in the left lane. Seriously get out of my way because I'm coming through.
People who ask questions that they already know the answer to. Yes I know, you hate that awkward silence, but you don't have to ask stupid questions to fill it. Chances are if there is that awkward silence I really have no interest in talking to you so just leave me alone.
Hypocritical people. Especially the ones that are bosses / in a position of power. The ones that yell at you for doing something, when they have done the same thing.
Grammar / spelling nazi's. I'm dyslexic, not stupid. Yeah sometimes my spelling isn't the greatest but pointing that out without commenting on what I was talking about is the exact same as saying "I know you are right but I cannot admit it so I'm just going to find something else to insult you with and argue over."