Well when I first learned to sail I took a sailing course where we had to sail our boats up a really narrow channel full of other moored boats. On my second lesson we were tacking out of the channel towards the bay and on one tack we were heading straight for a boat on a mooring...I was 100% sure I could feather the boat up into the wind and pass on the windward side of this moored boat.
Well...turns out I couldn't and I ran smack into this boat while my instructor was freaking out and the other students were flailing
fenders all around trying to minimize the impact. The worse part is about 5 minutes after the "incident" my instructor said..."did I mention that was my boat you just plowed into?"
Fortunately there was only a little scratch in the gelcoat but I learned my lesson and have never made such a stupid mistake since.
Bob