.. is when you realize that you have forgot a password for your GPG private key which you have been using quite actively for 3 years. Memory plays dirty tricks sometimes - I was able to recall this password 15 mins later.
As soon as I saw it, it struck me that of course this was my PIN.
I guess what happened is that I forgot the number, and relied on muscle memory to push the buttons in the right order. Then one day I forgot the number and couldn't remember which buttons I'd press for my ATM card (vs. buttons I'd press for something else).
