I do a lot of that. I always have.
I have even more time for it now, even if I have to take some care on not pushing myself into fatigue with concentrated effort.
A more easy pace is required: I'd not be able to play chess well, pursuing down chains of moves, that would be far too demanding.
Solitaire marble puzzles are proving a good level of distraction when rest is required but the mind will simply not lie still.
I've got to playing with new formations, just for the variety and fun.
Words and language also get considered: watching language drift and change.
If enough people use a word wrongly, the same way, does that become the real meaning? Meanings have migrated in such a manner in the past, and some modern ones can be spotted.
Then there are the modern fashions, and words that need retiring, or rescuing, or putting up against a wall to be shot.
No, I am not a grammar Nazi, I am a grammar Rommel: while I fight in the cause of good language, I may turn on my own side if it becomes too tyrannical.
Poor "ultimate": popular, but rarely if ever truly meaning ultimate, these days. It just gets pushed into place as stronger than "new" or "latest".
"Your ultimate holiday destination/experience"
Do they shoot you after the holiday, or ban holidays so you can have no more?
Poor "affect": a perfectly good word, but the usurper "impact" has almost totally taken over, even where it is a poor fit, simply because it is thought to sound more forceful.
Or worse because many now think it is correct, or the fashion.
The Olympics and Paralympics television commentators were almost without exception fond of "quicker" when standard grammar would require "more quickly", "easier" instead of "more easily".
It may be what would have earned me a black mark in my English lessons is now normal practice.
In which case it's another marker of me getting old.
I must do some more careful listening and reading.
No, I don't spend my days actually thinking about my CFS.
It doesn't dominate me that way.