When I played games I realized it was for those rewards of accomplishment. I felt good about myself for a few minutes when I beat some hard level. Its worse when you are not getting those rewards elsewhere in your life.
Lately I mostly play Rocket League, which is mostly for social reasons (my friends dig it and live too far for me to hang out with), but is enough like a regular sport to have a sense of skill-building, competition and team cooperation.
The witness is sort of like a really fun math course that looks really pretty and teaches in a more interesting way. In real life I only occasionally get to solve interesting problems that I don't yet know the answer to. This scratches that itch in a way I have power over.
Undertale is an emotional story that I have agency in. It's one of my favorite examples of how game mechanics can enhance a traditional story.
Minecraft is a lot of things, but creativity and design are often front and center.
Writing this, I think a lot of games may be about experiencing things in a manner where people have more control than in 'real life'. It's also cheaper and faster than most hobbies. You can even get social status for being particularly skilled at games (see: twitch). Admittedly you probably won't make money playing games, but that's true of art, music, football, open source programming and most other hobbies.
It quickly became clear to me that they intended and succeesed at effectively creating a profit-making skinner box for humans.
Who knew the HS psychology class where we trained a rat to pull a bar for sugar water would later act as an innoculation for lousy games that manipulate their users via classical conditioning methods.
It's sad really because the Blizzard classics (IE Diablo 1/2, Starcraft, Warcraft 1/2) represent the pinnacle of visual storytelling in games.