a, e, s, and i - those letters wore off pretty quickly, but now i am down wearing through the thin plastic, the e was first to go. yes, exactly that, long days of coding every day, well that and commenting on boingboing 
also, on a note of annoyance at apple, i have 2 of the new bt wireless apple keyboards that i don’t use, and figured i could pop off the keys and swap them onto my wired one, but nope. the key sizes are not the same despite looking visually the same. the tolerances are totally different as are the attachments under the keys. i was very dismayed at that. 
