I have gotten pulled over for speeding a few times, and once for an expired license plate (forgot to get the new sticker). Now, the option is to a. be polite and respectful, or b. get an attitude. I've exercised option a every time because they have guns and know how to use them, and even if they didn't have guns, they still have training in subduing people who are misbehaving. Even barring that, they can quite legally tack all sorts of added fines on to a ticket if they really want to give me a lesson on what happens if you're rude to a cop.
By exercising option a of being polite every time, I've been able with one ticket to get the speeding fine reduced. He put on the ticket that I was speeding, but put a speed less than what was on the radar gun, which put me into a lower fine bracket--this was about 20 years back so it may have been OK to do that then. Another time I got off with a warning because I was honest and polite. "I'm really sorry officer, I'm running late for work, and I have the worst migraine right now." "Ma'am, that means you should be driving even slower then." "You're probably right, sir." I must have looked like I had an awful headache then, which I did have. Every time I've been stopped, though, I've treated the officers with respect, and they in turn have treated me with respect and even kindness. We had a police officer come to our house one time to tell us 'your car is parked in the street'. I looked out the door and sure enough, our car, which has a standard, had rolled out of the driveway into the street (a certain male member of the family had forgotten to set the hand brake). It was dark out, and the officer made a point of letting me know about an icy patch on the sidewalk so that I wouldn't fall, and was just generally so nice about the situation that I actually called the police department the next day to let them know how much I appreciated how I'd been treated. He didn't have to go out of his way to be so nice, but he did.