Showing a guy that you thought was cool a hot spot, then going back a week later to find him and a couple of his friends there.

Leaving your $1200 sage/tibor combo on the roof of your truck, drive for 45 minutes then realize your rod is not in the vehicle. That hurt!

I beleive that I have done the flasher/fly into the drink as well, good way to spend 15bucks.

Oh yeah, forgot. When letting a buddy hook up a boat that you borrowed, always make sure he attached the trailer to the ball securely and that the safety chains are hooked up.