To make it St. Patrick's Day-themed, we can say that they're sleeping off a night of drunken debauchery.
Over the course of the day, people would comment on the shirt and I'd mention that I chose it to avoid pinches, and everyone over the age of twenty-five would laugh and share schoolyard memories of being chased or picked on because they'd forgotten to wear green. However, if the customer was college-aged or younger, he or she would look confused. Apparently - at least in the Los Gatos area - kids are no longer pinching on St. Patrick's. That's interesting.
In the bookstore, we sell little puzzle erasers from Japan that come in a variety of shapes, including different animals, toys, and foods. I noticed a much greater interest in the sushi-themed eraser set than we usually have on a Tuesday. Was this a subliminal influence of my shirt? I wonder...