How real do we want our fiction?

I like to read fiction. I also like to read non-fiction. There is something appealing about both formats to me. My question though is how much reality should fiction reflect? Should fiction be an accurate portrayal of its time period? Because it is fiction it has the liberty of playing fast and loose with facts. Should it?

I was thinking particularly about fiction set in the present time. As a reader do we want accuracy or fantasy? Do we want how life currently is or what it can be based on other circumstances? That is the beauty of fiction over non-fiction. Fiction has the ability to illuminate the human condition. It can show us not just where we are but where we are headed. Especially if we don't change the way we conduct our lives.