About T-Shirt Design
If you like shirts that actually have some personality, See Me Smiling Because Thinking Something Bad If You See Laughing I Already Have T-Shirt is a good example. Anyone who is into everyday humor will probably understand the idea right away.
It makes sense for birthdays or holidays, especially if the person already likes this kind of humor. It has the relaxed feel people usually want from novelty shirts without getting too complicated. The joke is quick, the message is clear, and that is really all it needs.