You're not perfect, you know. Not even one of us was born complete, with nothing to learn or change, without any kind of a flaw. Not even one of us leaves without something that makes him/her mad. We're imperfect human beings, and it makes us better persons, much more like able. A famous writer once said: "All perfect families are similar, all flawed families are flawed each family in its own unique way..." We all want to create like able characters, characters that are both easy to play and deep. The easiest way to do this is by giving the characters flaws and internal conflicts.
A flawed character is much more alive than a perfect one. When a character has to deal with a situation that confronts her flaws, she gets empathy from us. More than that, she is immediately reminds us of living people who had to confront with the same things. A character that has colour blindness gets our empathy when she attacks the wrong side, in the middle of a battle, because of colour confusion. A character that is afraid of dark places will remind us of Uncle Albert who used to scream for help whenever there was an electricity failure.
But flaws are only one of the ways. A much more interesting and deep way to make deeper rounder characters is by inserting internal conflicts into them. The judge who is haunted by his memories of sending an innocent man into his death, the pacifist who has to fight for her country to prevent her kids death, the champion who came to an age when the army doesn't need her anymore but who doesn't know how to do anything else... Suddenly, it's a richer character. We get a personality, a snippet of a life story, and a conflict that can help the character seems unique every time.
How about you? How do you make your characters richer?