About T-Shirt Design
The idea behind My Favorite People Call Me Grandfather T-Shirt is not trying to be fancy. It is just a fun shirt with a clear joke. It has a clear grandpa humor vibe, which makes it easy to picture as a gift or something to wear for fun.
It makes sense for Christmas or birthday, especially if the person already likes this kind of humor. People who buy t shirts for the joke as much as the shirt itself will probably get what this design is going for.
It has enough personality to be funny without looking like it is begging for attention.