About T-Shirt Design
I Don't Give A Rat's Ass T-Shirt works because it sounds more like something a real person would say than a random slogan. Anyone who is into everyday humor will probably understand the idea right away.
It could be a fun gift for holidays, casual days, or just because you saw it and thought of someone. It also fits in with funny t shirts for men that are more about a quick joke than a huge graphic. The joke is quick, the message is clear, and that is really all it needs.