A while back I saw my old Hobie Cat at the lake. When I tried to strike up a conversation with it's newest owner he presented himself as quite the authority on sailing and rudely blew me off. I held my tongue on a couple of obvious rigging mistakes and from the lake watched him raise both sails in the parking lot and back up when the boat blew over on the concrete.
Normally I'll help most anyone but in this case we just went for a nice sail.