I've worn this shirt a gazillion times in the past three years and I love it when people don't know what it means. :)

Not too long ago, one of my friends asked me about it. "Try it out when you go home."

"...just tell me what it does!"
"Er, type something and then try it."
"...it deleted what I wrote."
"Yup."
"..."

I think I ultimately had to tell him what it did.