According to Wikipedia, “A pet peeve is a minor annoyance that an individual identifies as particularly annoying to him or her, to a greater degree than others may find it.” I suppose that is accurate, but to me a true pet peeve is something small that you have a completely irrational reaction to. I’m talking from zero to RAGE in 0.8 seconds.
I won’t ask what your biggest pet peeve is, because I know mine changes based on which one has happened most recently, but what is the first one that comes to mind? For me it’s whistling in the car. Whistling in the car makes me want to punch someone in the teeth.