oh, and then there was taking my first boat (at 16) out in lake michigan in a storm only to find that the centerboard was the wrong one for it (didn't even clear the hull). then the guy who was riding with me chose that moment to say 'I can't swim'. And then things got worse.
Come to think of it I'm not sure I could come up with a 'best' bonehead move. I have so many, and they are all so bonehead...