Details. Signs. Instructions. Directions. Do this. Don't do that. Yada, yada, yada. Life is often full of too much information about what to do, how to do it, how to feel, and more. And then there are metrics about each day...how many hours of sleep, number of steps, number of floors walked up, resting HR, HRV... If you pay attention to it all, your head is likely to explode, or at the very least suffer from analysis paralysis.
When it comes to training, sometimes just training is more important that the details of what you actually do. Just f-ing train. Just do it. Whatever. Just don't let the thought process get in the way of actually doing it. Oftentimes, the difference between 4, 5 or 6 reps doesn't matter that much. Neither does it necessarily matter whether you take 60, 75, 90 or 120 seconds between reps. (Actually it does make a difference depending on what you want to achieve from the session...but for the purpose of this article, I doesn't!!)
If you're just wanting to enjoy fitness from training, push yourself a bit (or a lot), then just go and train how you feel. To that end, any kind of training will help your fitness - mental and/or physical - in some way...just like any food has some nutritional value!! And like with nutrition, enjoy a bit of everything and not too much of anything when it comes to what you do when you do get started.
Of course, this strategy will only get you so-far in relation to achieving particular or specific goals, but you will achieve enjoyment and satisfaction from it without the mental stress or anguish of worrying about the details. So on 'those' days, don't over think it, go by feel, forget about the details and enjoy the simple feeling of bring fit and active.