How much can you argue with a cop?

A during a trip home, I was pulled over for speeding. The cop had me get out of my car and sit in his while he wrote the ticket, stating I had been doing 67 in a 55 mile per hour zone. I was having car trouble at the time (hence the trip home to work on it), where my car would shake violently if I went over 60. He gave me a sidelong glance, paused, and stated that he’d do me a favor and instead of writing me a speeding ticket, he’d write one for not wearing a seatbelt. I started once again to protest, since the seatbelt in my car is automatic, it was dark AND I was wearing several layers of loose clothing. Another sidelong glance, and this time his hand “deliberately rested” next to his tazer while he did so, before he continued writing the ticket. I figured that would be the time to shut up, especially since we were behind the camera.
I doubt he would have actually tazed me, but I didn’t want to push my luck.

This is something I’ve always wondered, though. How much can you argue with a cop (being civil, obviously)? Anyone who’s been stopped, asked if they will submit to a search, only to have their car searched anyway with the refusal being used as “probable cause” might see where I’m coming from. Or is there a place that lists your rights during a traffic stop?