I am incorrigible when it comes to doing things I'm not supposed to when recovering from surgery, a broken bone, etc. It got so bad when I was trying to vacuum with a cracked sternum (yeah, I really did do that!) that I finally decided to consult with a doctor for advice how to get myself under control. He suggested I ask myself when thinking about doing something that I knew I probably shouldn't: "Is this in my LONG TERM best interest?" Puts what you want in the moment in the right perspective, doesn't it?
Applies to smoking that cigarette after you've quit, too, doesn't it? Smoking is NEVER in your long term best interest! So – just don't!