The coolest part about fiction, in my mind, is exploring the lives of other characters. Even stories that may be more "plot heavy" have fascinating characters, for those that don't usually fall flat.
For instance, you could have the bulkiest man--some sort of body guard or what have you--and if he's sad at the right moment, it would be the one of the most powerful moments.
See, one thing we have all in common are our emotions. In fact, even Darwin wrote in The Expression Of The Emotions In Man And Animals that all humans beings, at the end of it all, still share our emotions in common. Despite how evil or good you are, weak or tough, you still feel the same emotions as everyone else. How you express them is the interesting part.