I'm sure you've heard the expression 'truth is stranger than fiction'. Why is that, though? Well, for one thing, fiction has to make sense, and real life doesn't.
So if you get right down to it, fiction that is really 'realistic' would almost by definition have no plot, little continuity, and unbelievable characters. Funny how that works, isn't it?
In real life, people don't need reasons that make sense. In fiction they do, or your readers will either throw the book away, complain, or both. Why is that, do you think?