Quote: I didn't stop reading at that exact point, because I had accumulated trust in the author to be better than that, but that has it's limits and they were exceeded.
-Morgan.
While I'd had some problems with the story prior to that point, I was only really reading it when I bumped into it and remembered it, as opposed to stalking for updates, as it were. So, it wasn't so much a 'How dare you, I'm leaving in a huff' moment, more just rolling my eyes and deciding not to bother picking it up the next time I saw it.
I admit, it's a pet peeve of mine, but I've found that stories about characters being beaten down, beaten down some more, and then beaten down again for good measure, tend to annoy the hell out of me. Going 'Oh, but in the end they'll be mostly alright!' doesn't really help, especially since this is often debatable. Louise wasn't the core of HO, but it was still frustrating to read, and the reason I moved on.
It's the same problem I'm having with Desperately Seeking Ranma, actually. We've seen enough chapters of the Senshi being humiliated and beaten, let them climb back up, dammit!
Also, Legend of Korra. It's not just fanfic that does it!