According to somebody I know, who is the least polite person while driving:
Passing lanes: she is speeding up. You should know she is preparing to cross into your lane. Prepare to die.
Parking : she is parking her car, she doesn’t let you know by signaling. Prepare to die.
cutting off a car: she is a half a block away from you, and you are turning into her lane, you just cut her off. Prepare to die!
cross walk. you have the right of way. prepare to die. She has the right of way. she doesn’t see you.
distracted driving: she is trying to find her cigarettes, lighter while driving. you are dead. she is drinking her timmie’s. you are dead. she just answered her phone on speaker. you are dead.
she is on the road, prepare to die!