A lot of times, I'll drop books by accident. I don't even mean that in the "haha, I physically dropped the book" either. I'll be partway through a book but have to put reading on pause due to life stuff, then when I finally get around to where I can read again, I won't know wtf is going on where I left off and won't feel like starting over again.
Other times, there were books I wish I could've dropped, but they were assigned reading at school. Most of those were some of the most boring things out there and one of them actually made me so physically sick that I had to vomit.
And recently, I've been considering dropping a webtoon because the current chapter just feels like a crappy crossover fanfic. Literally, between the previous and current chapters, MC1 has given up on the main plot and went off to date some random no-face guy, and MC2 who has been in love with MC1, has started summoning a character from an entirely different webtoon to hang out with. You can't tell me that isn't something a fanfic writer would do to make their ship work. The creators are even monetizing the anxiety and confusion because they've literally said that if you're worried about what's going on, you can donate $40 for a recording of their talks about future plans and where it's all leading.