My favorite was not something I did. Read about this years ago, maybe in bass and walleye boats or something.
Two noobs pull up, back down the ramp, one gets in and the other backs the thing up. Guy in boat cranks engine but it won't back off trailer (rear straps still attached). He motions to the other guy to do something, so he did. He disconnected the trailer. But it was low enough that the guy in boat didn't notice. Guy cranks boat, backs up and goes to dock. Never looked at the truck which now had no trailer attached. They both get in, pull away, hammer it and they are going about 5mph. Can't figure out why it won't go. They finally give up and one gets out to go back down the ramp to load the boat. Yells "someone stole our trailer". Eventually someone points out that their boat is sitting awfully low in the water and appears to have something hung on it. Namely the trailer.
I assume it was a true story but it does sound quite ridiculous.