> I can't count the number of times I've been caught in some huge knot of traffic pacing a cop who's driving two or three MPH under the posted limit, as if he's daring people to pass him...

I saw that all the time on my way into work (internship) this past summer. I just passed the cop. What annoyed me was other people who refused to pass the cop.

I also saw, in equal amount to cops going too slow, was cops going too fast, oh well.