This is my biggest pet peeve (unless it is necessary to clear main intersection gridlock in which case it is the lesser of two evils)
Last year I had two super long and heavy pieces of wood in my car and this girl behind me insisted on riding my ass which was making me nervous. I probably shouldn't have gotten out of the car to say something to her because people can be nuts but whatever I did. She no word of a lie had stopped a hair width away from my bumper. I walked up to her window and said "Get off my ass because if you eff up and slam into the back of me a giant piece of wood will likely come smashing thru your window and it's not going to be pretty"
By the next intersection she had changed lanes lol