I Apologize To No Computer! Ctrl + Z Cards
These Ctrl + Z cards let a computer savvy recipient know you wish you could undo a particular operation. Probably not a bra strap either, although you're welcome to try. Just don't come crying to me when you get your face Ctrl + P'd with an open palm. Kidding, I'm here for you. Yesterday. I'm here for you yesterday. Call me when you invent a time machine.
The ultimate "I'm sorry" card? Yes! [myextralife]
Thanks to Lisa, who sends anthrax-laced delete cards.