It ain't a bad plan to keep still occasionally even when you know what you're talking about.
The worst waste of breath, next to playing a saxophone, is advising a son
"Why doesn't the fellow who says, "I'm no speechmaker," let it go at that instead of giving a demonstration? "
A loafer always has the correct time.
Nothing dispels enthusiasm like a small admission fee.
Nothing is as irritating as the fellow who chats pleasantly while he's overcharging you.