eksasol: If you're looking at alone and moody, you should try some hiking games, like Morrowind w/ Overhaul mod, Oblivion or Witcher 3. All good for that purpose, don't have to do the main quest, just explore around. I think The Long Dark may work too, but I haven't played it yet.
I still think No Man's Sky is the best choice, for this purpose. Alternatively, I heard good things about Empyrion - Galactic Survival, but it's not on GOG. (And Steam is down).
Or Pokeman Go.
There are few sailing games I might recommend like Sea Dogs, but can't say they are not frustrating.
Just play Super Mario World.
Thanks for more ideas. I still think it's best to wait with NMS. I am sort of "patient gamer"... if you know what i mean. Elder scrolls and The Witcher - good stuff, but I am a bit afraid of big games like that. Why? Because when I start something, I usually push myself to finish it. And lately I feel better experimenting with shorter games. Anyway, I loved Morrowind when I played it - great times :-)
