When I didn't have a computer, I sometimes passed the time by using a deck of cards, for what in the UK we called "Patience". In the US, we usually call solo games "Solitaire".
For some years now, I have been restricting myself to one hand of "Free Cell" a day, to control my addiction to the game. However, when I began playing this game a few years ago, I didn't really "get it". The version of it that I now play online, allows one to go back to start if one gets "stuck", or to go back a few steps if you see a better way out. With that, I brought my success average from somewhere around 50% up to about 98%. However, unless you restart at zero, the statistics continue to build up game after game. Recently, I worked up from that low level, as far as 90%. I recently achieved that level, including all those old sub-par games.
At that point, I decided to try to start all over. Unfortunately, there was some kind of problem with the system so that I found it hard to delete the last unsuccessful game. It kept appearing every time that I tried to restart from scratch. (Every time you have to abandon an incomplete game, that's one loss in the statistics.) Finally, I found that there were some controls that I could apply, so that I could start over at zero. At the time of writing, I am still at 100%, but that reflects only 26 successful games out of 26 tries!
I know that in due course I will come across insoluble deals, and I'm ready for that. I just never want to fall below 95% again!