We are not allowed to wear printed t-shirts (pictures or text) at work. We had been allowed dress-down in that format on weekends, but there were some incidents where people either abused the privilege or completely failed to comprehend the difference between work-appropriate printing and the kind of funny you can find at tshirthell.
Today? Some wingnut came in wearing a "You'd look better NAKED" shirt. Then didn't go and turn it inside-out when directed to. Then (after Obso1337 Super had words at him involving the phrase "You will not disrespect MY supervisor") felt singled out.