Know that situation where there's what you want to say, and what you do say?
"Hey, there's a problem with that gun I rented."
Grab earpro, go out.
"You stupid bastard, why the hell did you try to take it apart?!?"
"That is the disassembly lever, DO NOT MESS WITH IT."
I swear, some people need to have a keeper. Preferably with a taser.