Things that piss me off:

When I need to get out of the store quickly, and I think I've chosen the shortest line, and then the person in front of me has to get a price check on what they wanted to buy.

Same with traffic. No sooner have you picked the lane that you think is moving more quickly, then that lane stops, and the lane that you just left starts moving.

I'm sure that I can think of many, many more, but those two are serious hot buttons to one of the most impatient women in the world!!