On the morning of your friend’s wedding, if you’re trying to calm his nerves by projecting an air of calm, unruffled “this is a piece of piss” confidence, try not to walk head-first into a door with sufficient force that your specs puncture one of your eyelids. For some reason the groom’s faith in your fundamental unflappability is dented somewhat if a river of blood is running down the side of your head.
It turns out that his confidence will be dented even further if, when you try to prevent a black eye by holding a bag of frozen veg against your eye socket, you start shouting “Aaaagh! Brain freeze! Brain freeze!”