Has anybody wonder why people wear shirts like these on fridays, on weekends, or on days they don't have school?

Well, I actually wear shirts like these mostly on weekends.
If there's a party, like a birthday party or some party, I would wear a shirt that would be like the Peace shirt on the right, the yellow Bart Simpson shirt, or maybe a shirt that might say 'Lets party!' or something.

If it's friday and I am at school, I would wear either the shirt on the left or the right. If there's no school and I'm with my Mom at Apple, I'd wear an Apple shirt.