Early morning launch on Lake Okeechobee back in the late '80s. Guy next to me is backing down, about halfway down the ramp. I hear a loud crunch and a bunch of hollering. His nice, fiberglass boat is laying on the ramp about 10' from the water. He had silicone the trailer bunks the day before and unhooked the bow strap before backing down. One hit on the brakes and off it came. Several of us had to lift the bow up as another guy backed the trailer underneath the boat. Don't remember the damage but it taught everyone there a big lesson.
Then there was the time I tried to launch my boat in Destin, FL without taking the back trailer straps off...and the time I put the drain plug in the wrong hole before a tournament in the Everglades. Fun times...