Beyond the obvious, that I just do... for me, it's really how affecting those "harder" contemps can be. There is nothing better, to me, than going through an entire emotional battle while I read. On a bad day, when I'm fed up with things, and tried, and frustrated, or just plain exhausted, there is something invigorating about being locked in someone else's pain and frustration. Not that I am glad they are suffering, plus when it's done right, I'm suffering right there with them. But it's such a good reminder that those things that seem so huge in my life, maybe aren't.
More than that, though, is that feeling, when you put a hard and emotional book down at the end, of being changed. Of having the way you view things changed. Of seeing a character's life, from their side, rather than the outside. Finding out what's really going on in that house down the street, or understanding why that guy spends all his time getting stoned and messing around. I'm not saying that is every character, or every situation, but there have been countless books that have honestly affected me, and even changed me, however subtly.
And as a writer, that's what I want. I want people to walk away from my books gutted and broken, but pieced back together in some way. I want them to think differently of something, however seemingly minor before. I realize that's a tall order to feel, but it's one I'm striving for all the same.
I love connecting to a character so strongly, I lose track of time. I forget what's going on around me (until, you know, Toby pees on my carpet to get my attention...). I love being angry at the other characters who wrong them, cheering when good things happen, and having so many questions about them in my head of things that aren't in the book. The books that leave me aching, that leave me breathless, are the ones that, a year later, I still remember. Not just remember that I loved it, but I'll remember details. I'll remember why. And the ones that really get to me, that leave me gutted for days? Those are the ones I reread.
Characters are always the biggest thing in a book for me... and contemporary books are far more intrinsic and character focused than the paranromal and dystopians. In the latter, so many of what's effecting the main character is extrinsic. Yes, there is an internal element too, but it's different. The non-contemps that end up being my favorite either have a very strong character development component, or the book is primarily contemp, with a touch of something else.
So that's why contemporary, for me. Personal taste, sure, but even more than that, it's what those books to do me, and for me. It's seeing these struggles, so many of them actually pretty ordinary when you get down to it, and how different characters react to it. How their lives have played into who they are now, when we meet them.
It's knowing, when I'm done, that no matter the crap that I get thrown, it's not really so bad, and I've been pretty darn lucky in life.