I get like that, and it drives me crazy, too. Sometimes everybody around me pisses me off; they can't do anything right. (I scare myself when it's my loved-ones that I'm annoyed with. I don't want them to experience that!)

I've begun to discover that when I'm not compassionate toward someone else, usually that means that I haven't been compassionate toward myself. When I really let myself feel what's happening within me, compassion comes much easier. 

Someone slowing me down in traffic and I'm mad, telling myself how they're wrong, it's all their fault... then I take a breath (or five) and notice that I'm really scared. I'm going to be late with an appointment with that person who looks down on me anyway, judging me as disorganized, disheveled, inadequate. Oh! That hurts! 

Lately when I get annoyed, sometimes I can remember to ask myself what compassion for me would look like.