Someone I know who grew up smoking, and finally quit after 20 years, told me once that for a good 15 years after quitting he still reached for his phantom pack in his breast pocket each and every time he got into his car.
I have found myself going to call a friend and stop myself from using a phone number that has been out of service for years. I always marvel at how my fingers remember passwords that other parts of my brain cannot. If I am forced to write down a password without a keyboard, I inevitably get it wrong.
The other day I tried to teach my daughter, upon her insistence, how to tie shoelaces. I tried to do it logically, step-by-step but it was an exercise in frustration for both of us because I kept messing up. Believe me, I can tie my shoes. I do it everyday more than once without thinking, even a little.