I suppose I'd have more respect for it if cops ever drove the limit

In the UK, the motorway police always drive at the speed limit (except when they're answering a call, obviously).

This is really friggin' irritating, because nobody wants to speed past them; meaning that traffic that was flowing smoothly at 85-90mph suddenly slows down to 72mph to eek past the police car so that they can speed up again.

Note: for reference -- the speed limit on a motorway is 70mph; average speeds on the M11 (London-Cambridge) seem to be about 85mph; average speeds on the M4 (London-Wales) seem to be about 95mph.