Fifty Shades of Grey, by E. L. James
I know, I know. I'm ashamed of myself, too-- so much so that I waited a month or two to decide whether I should even admit I'd started reading it at all. What can I say? I was curious. I should've saved myself the trouble, though, because everything you've heard (about how awful it is) is 100% true. The quality of the writing is terrible, and it's thoroughly horrid in several other ways-- and I can't understand why it's so popular! A certain percentage will claim that they read it (and possibly even the two sequels) just to make fun of it-- then there are those of us who were just curious and wanted to see what all the fuss was about-- but that still leaves a lot of people (women, mostly) who are reading them and honestly enjoying them. It's baffling. (To each their own, etc., etc., but still it is baffling.)
It was poorly written from the first page. Unsurprisingly, it didn't get any better, so I skimmed ahead to the infamous contract. That was enough to scare me into DNF territory, so I stopped. (From what I've read, though, most of the scarier and ickier aspects of the contract never come into play... but I already felt dirty enough at that point. Gross.)
I won't go into details, because goodness knows there are enough reviews out there, already (many of them hilarious and infinitely more worth reading than the novel itself). Unless you take some sick pleasure from torturing yourself with poorly written trash, I recommend skipping it.
One thing I will say, though, is that if I hadn't known in advance that this started out as Twilight fan fiction, it probably never would've occurred to me, because the similarities are only superficial. (Of course, I never saw the relationship between Edward and Bella as all that "emotionally abusive", so...) While I would never describe the Twilight series as really good, well-written books, I did enjoy them (after a fashion)-- the first more so than the following three. Compared to Fifty Shades, maybe you can make a case for Twilight as decent fiction. ;o)