Have you ever read a book that you can't help but look at and go, "There's no way that would happen."
I call these my Not Likely books. My favorite would be Perfect Chemistry by Simone Elkeles, book review can be found here. These are not the books that are so terrible you want to throw at the wall, or the worldbuilding is incomplete and doesn't make sense. These are books with realistic traits (like a relationship, mostly) that you want to scratch your head and say "Why doesn't life work like that?"
Or, "Why, when we write, don't we paint a realistic portait of the world?"
I'll tell you why: because nobody wants to read a realistic portrait of the world.
A lot of life doesn't have meaning. Or, at least, if it does, we aren't able to see the full picture in our short lives. A man's wife dies while he's away fighting in WWII. He comes home, living the rest of his life alone, until he finally dies of lukemia at the age of 62. Now, there's a great potential for a good novel in that premise. You can have a lot of conflict, character driven action and real heart. But in fiction, characters have to acomplish something. They have to overcome their conflicts. If this premise were to be turned into a novel, this man might have to overcome his own depression and selfishness, his bitterness, or he may have to overcome the society that is denying him his wife's life insurance. Whatever. Even if the victory is small, the character has to acheieve some kind of goal.
A book in which this man tries to overcome his bitterness, then fails, and then retreats back into his house and dies alone wouldn't be very satisfying. There are plently of real-life stories of people giving up, failing, dying, leaving, whatever. We don't want to read about someone who doesn't succeed, even in the smallest way.
Reading is an escape from reality, just as television and video games are. We don't want to escape into a reality in which characters fail. We want to see them succeed in what they need to succeed in, so that we have hope that we can succeed in our own lives.
Hell, look at memoirs. The ones that do the best involve the writer overcoming the odds in their life. The fact that it's true draws people to it.
So yeah, I love Perfect Chemistry, but is it realistic? No. But if it was realistic, I wouldn't love it nearly as much as I do. Sometimes, as writers, we need to allow ourselves to step away from reality and venture a little bit farther into the world of make-believe.
Also, exciting, crazy news! I've got a twitter account. You can drop by if you'd like. I don't have much up yet, but I plan to get the ball rolling soon.