...when refs have botched the game and let one team go out of its way to be ultra-aggressive and then when that team that has been getting away with bloody murder needs to foul in the closing minute to stop the clock the refs automatically blow quick whistles on the most minor of contact to stop the clock. I've seen it sometimes where they are anticipating contact and blow the whistle just as the contact is happening instead of after the contact is made.

Don't reward one team by letting them turn the game ugly and then when it's convenient for them start calling ticky-tack fouls so they can stop the clock. Be consistent.