* The idea that I have to have my soul stuck in a cave for all of eternity just because of some crummy 3rd rate deity is awful. I mean really? Torment myself for all eternity just so I can help a guild which makes ordinary people's lives miserable? I'd rather spend my afterlife eating barbequed meat and drinking wine with the heroes in Sovngarde. That's far better than having my spirit stuck in a dank, dark, cold cave forever.
* Extortion, loan sharking, corruption, and such are things I really hate in real life. I didnt' want to be involved in supporting all that disgusting stuff. I just wanted to get some interesting quests that would improve my sneak skills. It would have been nice to have thief quests that were about stealing fabulous treasures from corrupt people and corrupt organizations, like they did in the Conan the Barbarian movies.
* I'm a very independent person in real life who absolutely can't stand being under anyone else's thumb. But you railroaded me into this quest line where I'm supposed to enslave myself to defending a 3rd rate goddess both in life and in death. NO. I won't do that. That is awful and unacceptable.
* In real life I believe in honesty, integrity, and doing the right thing. My philosophy is more in line with Mjoll the Lioness. I basically got involved with the thieves guild just to find out what the unusual gems were. Up until then I had avoided stealing anything at all.
* I would much rather have a quest line where I get to humiliate and kill Maven Black Briar, free Riften from corruption, and destroy the thieves guild. In real life I hate all the corruption in government. That's the kind of thing I'd like to destroy, not support! The thieves guild to a large extent is about undeservedly taking a cut of everyone's profits. In real life that's basically what the government does through taxation. I hate that.
You may say it's just a game, but as a player my enjoyment of the game depends on liking the kind of role I'm playing in the game's world. I don't enjoy playing a scumbag and I don't enjoy being stuck forever in a filthy cave after I die.
I will say that the Nightingale armor is the best looking, coolest, most beautiful armor in the game, so it svcks that the way to get it is to finish this awful quest. This armor is so cool looking that I could imagine an entire game being made around a character that wears it.