Shirts That Go Hard

I wore a tshirt that said “Happy birthday, Fucker,” (it was band merch, a song lyric). A guy commented similarly (“happy fucking birthday to you,” or something similar). I didn’t understand until maybe five to ten seconds later when I remembered what my shirt said. It was the only time I wore it in public. I wonder if the person with the Robocop even put it together; had my commenter not sounded hostile, I probably wouldn’t have thought about it at all.