About T-Shirt Design
Pog Mo Thoin I'm Irish T-Shirt works because it sounds more like something a real person would say than a random slogan. Anyone who is into St. Patrick's Day will probably understand the idea right away.
You could wear it for parties, bring it out for parades, or just keep it in the normal shirt rotation. It works well as a novelty t shirt because the joke is clear and the design has plenty of personality. For a funny t shirt, it keeps things pretty straightforward and lets the saying carry the humor. The design is easy to get, easy to gift, and easy to wear without overthinking it.