Oh my gosh, so many things annoy me...
People who stop at Yield signs when there is no one coming. Do you need a dictionary?
People who aren't ready to pay when the cashier is done. It should not be a surprise that they would like your money before you leave.
People who fail to follow very simple, concise directions then get pissy when they are unable to complete their transaction. I told you i need to see current government-issued photo ID. If you had told me on the phone that you were coming in with your birth certificate and work badge, I would have happily saved you the trip.
People who show up at my place uninvited and unannounced. If I'm naked and rubbing one out on the couch on Sunday afternoon, I won't feel obligated to answer the door. Actually, I won't feel obligated to answer the door no matter what I'm doing.
Also agree with the poster who said the people who don't decide what they want to eat until they get to the counter. Oh and how about the car at the ATM that takes so long to find their card? Did you not know you were driving there?
I guess all of these things can be summed with one word - rudeness. A lack of consideration for those around you.
Oh hey how about the out-of-control children running around restaurants while their parents sit there acting like they don't know them? So far I've been able to resist the urge to just trip one of the little brats, then explain that never would have happened if they had parents who cared enough to teach them how to behave in a public place.