Not gonna differentiate between amateur writing and professional writing here, since I tear through hundreds of pages of fiction a week when I have free time, which makes remembering what something is from a pain. It also means I read a lot of crap. Generally, I put something down for one of the following reasons:

1. Obnoxious reactionary politics. Someone starts pushing fash shit, I put the book down. Sadly, more common than I'd like.
2. Major grammatical shortcomings. Not a typo or two, those are fine. Consistent poor use of punctuation, tenses, or anything that consistently distracts me from actually reading.
3. Grinding misery. I can deal with hard things happen to a character, but if the whole story is just misery after misery, I'm not gonna put up with it forever. Example: Name of the Wind. Just, constant grinding misery and it almost always the MC's fault in the microcosm. It's a fine introduction to why poverty is self-reinforcing (everything that can fuck you over will fuck you over, and all of your available decisions are variations on bad ones), but it is also miserable to read.
4. Certain kinds of being too real. I struggle to read some trans-centering literature explicitly because it either makes me feel incredibly dysphoric or because it just re-triggers my own sore points. This can be hard to predict ahead of time with a text. I experience this most often in the context of fanfiction.
5. Tension without release. One of the trends I see in fanfiction over 200k words is a tendency to not be able to allow pressure off of the story for a little while before bringing it back. Arcs are either not fully resolved, leaving no downtime to the story or the author can't help but continue escalating. This is a bit like grinding misery, but not the same. I find it exhausting. If I wanted to deal with an unending grind where things never get better, I'd go outside.