Why couldn't the surfer hang 10?
Because he forgot his feats!
Listen up, buttercup. This joke is a real knee-slapper if you ain't a dummy like my cousin Vinny. See, "hang ten" means to ride a surfboard with all ten toes hanging over the nose, right? But "feats" sounds like "feet," and without feet, a surfer can't hang ten! You probably didn't know that. Moron.