why do the police speed?

I have seen cops here blip the lights to blow through a light that just turned red on more than one occasion. Block later they shut them off and proceed on their way. It's well known they drive over and tailgate to "intimidate" people to speed. Or "pace" people and say they were going over. Lots of other things. But occasionally they do pay the price!

Police officer ticketed after crash with failing to yield