I'm usually more fascinated with writing games than playing them, but there are a few I play regularly.
I used to play TrackMania Forever sporadically until I accidentally logged on to an "RPG" server. Now I play it for hours most evenings, and have done for years, although these days I probably spend more time using the in-game chat than driving.
The "RPG" here doesn't quite mean the same thing as usual, but refers to a community-driven genre of map/track. RPG maps are usually long (it can take literally hours to complete one) with very hard jumps, trial-style balancing acts, and pathfinding. Most have a "mod" (texture graphcis pack), some sort of story line and block-mixing. The latter means using a hacked version of the track editor to superimpose blocks, which wasn't an officially supported feature of the game, but enables great creativity (and some flickering abominations if misused).
I consider this one of the best games ever, considering it was originally created in 1985. Most people prefer Repton 3, but I love the way Repton 2 had interlinked levels, forming puzzles within a puzzle. The original version was almost impossible to complete, but being able to save the game in emulators and versions for more modern platforms changed that. Visit my Youtube channel to watch me play, including complete walkthroughs.
I like puzzle games such as the Portal series, The Talos Principle and The Witness. I also got hopelessly addicted to Infinifactory, but consider it to be in a slightly different sub-genre from the others above.
I used to enjoy FPS, especially if they had a good adventure/puzzle element, such as the Half Life series, most of the iD Software classics and the first few Call of Dutys. Not quite FPS, but I enjoyed most of the Tomb Raider games. ROTR was a disappointment to me, emphasising the fahsionable gameplay elements over what made (some of) its predecssors distinctive classics.