Welcome back, I hate all these passwords and pin numbers and all sorts.
Just to talk to someone about my university finance I have to quote three codes, each 12 characters long. A reference number, and 'ART ID ' (Whatever that is) and a secret password!
They even ask you not to write them down and destroy the paper they send it to you on for security reasons.
Couple all of that with a few pins for cards, maybe a pass number for a door and various internet things, it's completely understandable to forget a few, or write the odd one down!