Everything in moderation and nothing to excess. If you want a burger, go eat a burger (preferably without the bread/roll), just don’t eat one every day. If your body is just not feeling it that day, do gentle, short stretches instead of intense exercises, but do something! Practice moderation and know the difference between being tired and being lazy. Tired means something is letting you know that perhaps you need to relax or take it easy; while lazy is just you not wanting to put the necessary effort into doing something. It's okay/natural to be tired here and there, but not lazy. Lazy is unacceptable in the healthy world!