sometimes I guess, depends on the characters and how it all develops, that's also why I often quit once a character does something out of character, just to progress the plot, be it doing something stupid or similar
It is really dependent on what kind of novel, no? If it is against the tone of what they are writing then I may not even like a happy end. With novels with themes of revenge, I feel like a bad end could be well done.
I don't get emotionally attached, but I do walk away with a good memory of that novel if it was a good in my opinion. stellar transformation was one such novel for me, but maybe it was because it was one of my first novels. TDG was my first Chinese novel.
I do remember a few times I was literally crying at points in a story, though can't for the life of me remember which ones they were. Translated eastern amateur novels are typically on the level of bad fanfiction, so they rarely evoke emotion from readers, but some that are good can make you emotionally invested.