For me, it often ends up being "Do I want to play this game? No, because there's this one part I don't like.". It's happened to me with multiple games. For example:
* SaGa 2 has one part I consider boring, namely the part where you go into someone's body. Thing is, the dungeon has mostly old enemies, it takes a while, it's non-linear (so you need to remember where you've been), and there are no treasures. (Well, except for one excavation point that the remake added that gives a random stat boost potion; I believe it's at the end of the intestine, though I could be wrong.)
* Final Fantasy 6 has a rather nice non-linear late game (once you get the second airship); the problem is getting to that point in the game.
* Chrono Trigger, while a decent game most of the time, has one mandatory button mashing segment, which is enough to make me not want to replay that game.
* And, of course, Zelda: Ocarina of Time, which I won't replay because of the insta-fail stealth sections.

There are many games, way too many in fact, where even a few minutes is not enough to get to the actual gameplay.

Maxpoweruser is exactly right with choice paralysis, though I'd also say there might be a mix of post-game depression and maybe some gaming burnout in there too.

Some people enjoy sandbox games a lot, however don't complete it. I believe this is because completing the game for some people means having to say goodbye to a world they love since the overarching goal has been accomplished and the agency to play has been removed - even if there's nothing stopping you from continuing to play any remaining postgame content.

I think it's important to have another non-gaming hobby to go back to for a week or two and then come back fully revitalized in playing another game. If this isn't do-able considering your disability OP (sorry to hear), then another non-thinking, relaxing game can be a good substitute until you find another game you're ready to jump into with a lot of personal and emotional investment to spare.

Something like Stardew Valley, Townscraper, Islanders, driving or job sims, hidden objects, racing games, etc.

Happens to me sometimes, not just with games but with anything immersive that I play or watch or read for a long time. Usually it's worst with long tv shows. After 6 months or so of watching The West Wing or The X-Files it's almost a bit unpleasant to sort of mentally shift gears for a different show and different characters.

With games it's maybe less accute because I rarely play anything for nearly so long, but on the other hand there's the added annoyance of having to learn the game if it's something I never played before. I like being able to just open the game and play, without tutorials or looking up how something is done.

I understand that. That's kind of my point. I may not even get into the game before I am turned off from it.

It doesn't really happen to me because I only finish a few games per year and always have a few games that I dropped at some point but intend to continue, so if I do finish one, I'll usually first look through those temporarily dropped ones (where "temporarily" may well mean several years) and see whether I can get myself to continue (sometimes I surprise myself and get past whatever made me stop almost right away, fresh take maybe). And then there's the weak computer and 32-bit OS that severely limit the options at the moment. Then I have games split between backlog and uncertain, and I tend to take some time around the beginning of a year to also sort backlog into planned for that year, tempted to try it, maybe, unlikely and not that year, and if I feel like playing more or less seriously, I take the list from the top and see what seems appealing at the moment, out of what would work and also considering how much time I want to dedicate (usually go for long and very long games, but when I find myself stuck in several or the end of the year approaches and I just want to be able to say I finished something, I'll pick a shorter one), so stop at the first one that seems to fit and try that. On the other hand, if I feel rather worn out or just want to give something a go and decide whether I actually want to play it or not, I'll see whether I can pick something from the "uncertain" list.

And yeah, also tend to have times way above anything listed on HLtB.

As for the collection of horses in Two Worlds, I arranged them nicely in one place, actually took me some time to make sure they were always in the right position when I left one more there.
And finished at level 95.

Mods are the worst for sucking up time and opportunity to play new, different games.

Case in point, new version of Long War of the Chosen for XCOM 2 just came out. There went another 100 hours and a month, when I could have been playing my backlog.

If I get tired of playing games, and am "in-between", I take a break from gaming. Simple as that. Come back fresh and eager, and able to enjoy the dopamine and serotonin properly.

Yes, it happens to me from time to time. I think the worst time was when I completed the Witcher 3, not just a game I spent hundreds of hours, but a series of games with easily a thousand hours on my back and almost a decade playing it. After that, it took me some time to find another game, it was like... "No game feels this good, no character is as interesting as Geralt, no game put this amount of details in side missions...". Now I'm playing Yakuza 5 and probably will be a series that will affect me.

Your second paragraph really hit home for me. Hesitation of starting a new game I've never played before is something that since manuals went away really, really, really hits me hard. The frustration of learning through "trial and error" and tutorials is just too frustrating and that's why I've been for some time only able to start games I've played before.

I mean tutorials... please. The most inclusive tutorial ever created doesn't come anywhere CLOSE to the level of detail that manuals came with. You know, like real info about stats, strengths and weaknesses of weapons/spells versus specific enemies, etc. The only way you learn this stuff now is through... trial and error (too frustrating) or read/watch a play through (don't like spoilers) so viola. No new games for me anymore. Thank you so much gaming consumers for not demanding manuals remain a part of every game. Cars, for example, still come with manuals.

Fucking toaster ovens come with manuals. Huge, complex, dynamic video games though... nope. Not only will you accept games without manuals, you will accept them unfinished and instead of paying for large scale beta testing we'll get you pay us for that honor. And oh yeah, when you "buy" (the word sellers always use instead of, you know, being honest and saying "rent") you don't really buy it because you really only rent it... and further, through forced patches we can completely change the game you originally purchased to something vastly different and you'll eat that shit too.

And gamers everywhere threw their mouths open and screamed all at once "Yes, MORE shit, PLEASE!"

I've never understood it. And never will.

To be fair I'm not a huge fan of manuals either (though I agree, they should still be present). What I like the most are games that either rely on familiar, well established mechanics and allow to skip tutorials, or introduce new stuff smoothly enough that it never feels like a tutorial. Ideally skipping a tutorial (and going back to it at will if needed) should always be an option.

I love point & click adventure games, because I can get a new story, a new experience with every one, but waste zero time on learning the ropes. Just start the game, and I can point & click my way through with no need for either manuals or tutorials. There's something so... I guess I could say "pure" about that.

This, but for other types of games as well. When a game has no more tricks up it sleeve, be it via mechanics or an engaging story, it often overstays its welcome, unless it really clicks with the player for some reason.

For RPG specially (maybe for adventures and mission based strategy games too) shortish games with easy to learn, hard to master mechanics, that meet a satisfying end and leave a good aftertaste are to be well received by a large portion of the public. Also, since today it is easy to add expansions, via DLC or standalone with the same or an improved engine, players might have a chance to get more if they wish so.

Consider the alternative: an admittedly long game that feels like a big investment and feels tiresome to start, or a game that you finally do not finish because it became a bore, and leaves you without that feeling of completion, achievement or even fulfillment (for good stories), isn't it anticlimatic?
This. Best of the best, a tutorial that is fun to play (because, remember developers, we play games for fun). If it appears to be a section of the game that does not even seem to be a tutorial, great.

This, too. Especially when it is not your first run of the game, or you already know the mechanics from a previous, similar game. So much true. It is exacerbated when you do not have much time, or the time to play consistently, but also with large backlogs. When there were few games, you just played what you had... Thanks for bringing this issue. Long games plus large backlogs and FOMO = hesitation. True. Game developers, hear.

Alternatively, a developer could include an intentional sequence break that skips the tutorial. The idea is that, early in the tutorial, there's a way that you can skip the rest, but doing so requires doing something that the game doesn't teach you until late in the tutorial. (I'm aware of one game that does this.)

Quoting myself from OP because I actually started TWEE again just as a bridge thinking when I died I would just start something else. Knowing I would be playing perma-death on the hardest difficulty I just figured okay I'll do this awhile and when I die hopefully I'll be able to pick my next game then.

Well, I still don't feel "hooked" to this game (it was just a year or two ago I played it last) but I still haven't picked that next game yet, and, well, I still haven't died yet (closest call was actually falling down damage rather than from enemies. I got that heartbeat sound about halfway down the hill and thought okay, this is it... but somehow got to the bottom with a sliver of life and... I'm now at level 55... so... maybe I will stick with this. I dunno.

The past few months of playing Gothic and Gothic 2 multiple times was so fun, and no thoughts about what I wanted to play, I was in the zone. I hate these periods I get sometimes after finishing long games. (Gothic isn't so long, Gothic 2 is definitely over 100 hours, and I played them both effectively twice, so... yeah... I was in the Gothic zone and it felt good. Sure hope I can find a new zone soon... but till then I guess I'll see if I can take this perma-death on hardest difficulty to the finish line.

I have something similar. When I'm looking for a new game to play, too many of the ones in my backlog look fun or interesting, so it becomes hard to pick one.

I'm avoiding lengthy games though (40+ hours), that's why in recent years I've focused on strategy games, point-n-click games, card-based games, wargames, etc. They tend to be shorter, either by default or by player choice.

So I avoid open-world games and rpgs.I also avoid games that require you to memorize a 200-page manual. Though these days you can find shorter guides on the tubes and websites for a lot of games.

This narrows it down to what I'll play next.Sometimes I do just pick a random game and say "OK, this is my next game to play, period".