a rude cop is the worst thing in the world.
i've met nice ones (was even introduced to a few who know 9/11 is an inside job!)
but when you do something minor (traffic offense) and you're nothing but polite and compliant with the officer, and he still talks to you like a piece of shit... well.. those cops do a great disservice to all police, and it lasts a long time.
I got a ticket once for running a red light in a construction zone in the middle of the night. I had been at it 5 minutes easily, middle of night, and it was a construction zone. The scale or sensor wasn't kicking in (this was 1996 i think), and after a while I just said fuck it, looked both ways, and ran it. Sure enough, some cop was watching and waiting. Gave me a $70 ticket. I was very courteous, but mentioned the scale. She asked if I wanted a seat belt ticket (I was wearing it at the moment - so she was going to have to falsify one).
I shut up and took the one ticket, but to this day, that cop has ruined it for other cops, just a bit. If I could stop and help that lady cop (who laid a trap then threatened to falsify a seat belt ticket for questioning her judgment), I'd keep right on driving.