I could drink a single beer. -Without having a second.
I could smile and act just like you with your single beer.
But when I said that one was "just fine", it would be a lie. In my head I would fantasize about not having to play this game and being able to just relax and enjoy 10 or 11 more.
Behind that smile -resentment.
This is MY example of controlled drinking. I cannot speak for him. But if I was to wager...