I'd buy one, but:
1) I don't have a credit card.
2) If I used my mom's credit card, she'd want to know what I was buying, and if I told her I was buying an angry face t-shirt from Newgrounds, she'd smack me.
3) I wouldn't be able to wear a NG angry face shirt in public, without drawing one of the following unwanted responses:
--- People who don't know about Newgrounds would ask me what the angry face was for, and I'd have to explain that it's a smiley face from a BBS, and they'd call me a loser.
--- Idiots would think it was Pacman, and comment on how much they like my Pacman shirt, and then I'd have to punch them in the face for being so stupid.
--- Other Newgrounds fans would notice the angry face, find out that I'm a Newgrounds member, and then follow me around and annoy me, and then I'd have to punch them in the face too.