Off the top of my head, the "Transformers" cartoon series. I know a bunch of adults who actually like it, and it's won many of the major awards for writing for animated series. I have tried to watch it. To me it seems much worse than I'd imagined, not even sophisticated enough for kids younger than its target audience, with characters I might've been able to stomach at age three but not at six. Nice graphics, if you like hyper-realistic overly-dramatic CGI more than style, character, or integration of visual presentation with story.
Wil Eisner's comics. He's known as the grand old man at whose altar all comic artists and writers kneel. I've read many of his comics, old (The Spirit) and new (A Contract With God), and they all had bad stories with bad characters, badly told. "The Spirit" had bad artwork besides, and made superhero comics look like great literature by comparison--and it came out around the same time as EC Comics, which were not great literature, but still a hell of a lot better.
There's an eight-strip arc in The Ferrett's old webcomic in which the characters try watching the old 1980s Transformers cartoon as adults...
I think it would be a useful rationality exercise to take something that millions of people love, that you have contempt for, and sincerely try to appreciate it. The purpose would be to get practice imagining a different point of view, and to see whether you're able to do so.
50 Shades of Grey might not be the best choice for this exercise. I haven't read it. Maybe a better choice would be The da Vinci Code, NASCAR, or professional wrestling. But a book has a definite length that you have to get through to be allowed to say that you honestly tried.
The idea is to start a thread for people to discuss 50 Shades, or something else perceived as trashy, and try--not to find what you might like in it, but to get inside someone else's head and imagine why they might like it. (Of course it could backfire, and leave you less open-minded than before, if you always conclude that your contempt was simply right in the first place.)
I think the biggest problem is that if people succeed at finding something to appreciate in it, they would feel terribly embarrassed to say so. So this can be done with alternate accounts.
Anyone interested? What do you hold in contempt that you might be willing to take a closer look at?