I can totally relate to that - well not the smoking bit. but yeah - a nice scotch and you can turn it off. Otherwise I find I will say "ok, I am finishing this.." go off and start talking to family/friends, and suddenly pause, stare into the distance, and then run to the nearest device of mine to try/make a note of some problem whose solution just popped apparently completely formed into my head.

but hey, we love this, lets not kid ourselves. Its great - so many people really hate their jobs, this is a wonderful business.