Tip if the driving is good and don't if it isn't.
Please do NOT reward bad driving.
Please ask your driver to pull over SAFELY and not stop in the middle of the road.

RP - loved your post.
add: don't assume the passenger wants to listen to your crappy music on a radio that isn't even tuned in.

I was once in a fragrant smelling taxi with Vivaldi playing...wonderful..and yes big tip.