Left a passenger-side fastgun connected on our old camper....tweaked the framing a bit but no problems from it.
Had the side awning open and flap in the wind of South Park (very very windy place) at 70MPH. No damage but learned the dual-use of the "deflappers" because you can use the velcro straps to wrap around the awning supports to insure they stay closed.
Left the Heiki unlatched a few times and pretty well hammered the built-in shade.
Forget to put rubbers plugs in the bathroom sink and shower drains....which allows the trap water to blast out on bumps and splatter the bathroom with grey water.
Driven away while plugged into shore power a few times.
Jackknifed the trailer backing into a 5+ lane road with an extra motorcycle on the tongue and nailed the jacks pretty good (but I'm excused on this one since we had just driven through the night to a vet and had to put our big dog Jasper down.....we were pretty distraught at the time)
I'm sure I've done plenty more than that but those all come to mind.
Oh yeah, pay attention to what "experts" are doing to your own rig as they often do even dumber things than you do. I let a tow truck driver try to pull me around to get out of the campsite and into town...by my winch cable. Bad idea. I also let a new guy at Lance try to raise one front jack to get blocks under it that he had forgot to put under the foot.....and I watched way too long thinking "this is a bad idea" until finally I called a halt to it while the camper was groaning under the "twist" up front. That's probably the single stupidest thing done to my camper....I didn't do it but I watched too long before stopping it.
