I think there's a lot of mythos about what's required in acting. The way that actors talk about acting is generally quite punishing, and I think actors want to put forward the idea that they do all of this work because, you know, it's a post-De Niro world, when, largely, in fact, it's almost never true.
Whenever I don't have anything to do, I play Candy Crush or Scrabble. We actors have time between shots, which we need to kill. And we cannot call friends or family, as you are called at a moment's notice. So you need to do something which you can dispose of immediately when called for a shot.