I know it's bad, but there's times where I do. Maybe I'm just a hot tempered 22 year old, but I feel like I need to speak up sometimes. Times where I get passed by mere inches, right hooked to the point where I have to slam on the brakes or cut off or just general stuff that puts my life at risk, I get a rush of blood to the head and become frustrated. I'll try to catch up to them at the red light or a parking lot, sometimes reacting with anger, sometimes politely telling them to be careful.
This doesn't happen often, but it's really infuriating when a bad or ignorant driver almost hits me off my bike to get to their destination 10 seconds faster.