I've not had much to do with the police force, though there have been a few things Ive been annoyed about.
1) The fact that they pull people over for speeding yet speed themselves, cut in front of people at junctions and generally make a hash of their driving (happens in my town anyway).
2) Their "you are in no immediate danger so you did not have a crime committed against you" thing. About a year ago Mum was getting prank calls from a withheld number, and then they started on her mobile phone - a number she hadnt given to many people. Calls were being made in the middle of the night so we ended up disconnecting the phone. When she phoned up BT, mum was told she would have to phone the police to get a criminal reference number to get the number blocked, she phoned up and was told they only gave out those numbers to people in situations which were putting their lives at risk. Never mind that by having the phone switched off we were risking not being able to be reached by elderly relatives using us as emergency contacts
3) Hypocrisy - this is along the lines of number one but when I was young my father, a policeman, struck my mum across the face. She reported it, and also at another time reported that he had had us kids sitting on people's laps in the back of his car, but it was all swept under the rug, she was told he'd been "warned" about it. If the police force want us to follow the law they should damn well follow it themselves.