The stories I really like is where the guy at the home center sells them a standard 4" octogon box with a plain jane bar hanger to install... you guessed it, a paddle fan.
I also love it when I do an inspection on a service entrance & Henry Homeowner says " that's the way the guy at the lumber yard said to do it." I suppose Henry homeowner will go to a Dentist when he needs open heart surgery.
My first encounter with a home owner installed switch had the switch connected line to neutral. Owner couldn't understand why the breaker kept tripping.
Tom