or they get cold when the AC is cranked up because it's so hot out
...or maybe it was cold when they left the house and they got hot and didn't want to carry it, so they put it around their waist.
Yesterday I saw a guy walking in the mall with a sweater around his waist.
If you live at the beach, you learn pretty quick to dress in layers.
...and their name is probably Biff or Buffy..
I used to do that a lot as a kid. I imagined it was like that lower part of Roman armor
The lower part of the armor those tassels and stuff that's what I imagined when I tied my sweatshirt around my waist as a kid
But does a sweatshirt around your waist make you look cool? ...
I think Wunderscore has the best answer as some of them get cold depending on what's going on.