The most annoying thing people to my car is slam the doors. I just want to beat those people ( my fiances family mostly). I took them to the grocery store one time and after they put thier stuff in my trunk they slammed it so hard I thought my spoiler was a goner. Also I want to go nuts on people who like to lean against my fenders or sit on my hood.
Also when someone borrows it and puts 87 octane gas in it when they know I only use 89. RRRRRRRRRRRR