A good expression is easily understandable yet hard to explain beyond the words already used. This shirt says "If you don't like my peaches, don't shake my tree." It makes so much sense. But when I try to explain it, I speak in vague terms and personal anecdotes that try to illustrate a simple meaning. I think it works so well because everyone knows what it means to them right away. This early 70s shirt, with light spots from storage, is a great tee that everyone understands.