I love how my kids used me as their Get Out of Jail card when a BS peer would suggest doing something stupid:
Have you met my mother?
Once K1 had been particularly rude and dismissive to me over the phone and I jumped in my car and drove several hours to his school. He had no idea I was coming. When he arrived at his dorm after athletics , I was standing there waiting for him. I said, Get showered and changed because we’re taking a drive. After a very short drive around the block, I dropped him back off at school and he looked like he had just seen a ghost.
During the ride I very calmly said, If you ever treat me ( or anyone else ) like that again, I’m going to drive up here and throw your stuff ( not the word I used ) in the car.
I drove off without saying another word. Two years later he told me that day will be etched in his mind forever… LOL. Someday he’ll tell that story to his own children… Grandma may seem very sweet but she was actually a total bad*** when she wanted to be so watch out, Kids … 
K2 ( who was reading over my shoulder yesterday ) told me to fix one sentence above : I outline what the (reasonable ) expectations are IN GORY GRAPHIC DETAIL and then I chuck the reins.
I stand corrected. Thanks, K2.