People who don't know how to use an entrance ramp on a highway. You don't fucking stop when getting on you moron, it's called an 'entrance ramp' for a reason.
People who don't know how to properly navigate a traffic circle. Damn it don't fucking yield when NO OTHER CARS are in the traffic circle. Fucking GO!
Parents who yell at their kids at the top of their lungs in public places for non safety reasons. Keeping your kid(s) out.of danger is a.valid reason for yelling at your kid(s). Otherwise your belittling them for absolutely no reason in front of people and probably embarrassing them.
I shall stop for now.