Tell HN: Meditation has 0 Opportunity Cost

In thinking about meditation, journaling and exercise, I realized that (at least for me)...

__they all have 0 opportunity cost.__

For example, if I were to spend the first 20 mins of my 8 hour workday meditating, I get a more productive and happier remainder of my day than I'd have without the meditation. I realize that this doesn't _exactly_ mean that opportunity cost is 0, but it's a helpful mental model. Time expenditures that are 0 opportunity cost are by definition no-brainers.