I haven't been more excited about a TV show since Breaking Bad and Game of Thrones. The show has taught me a great deal about characters both on the screen and on the page. Here are the six 'main' characters and a brief character profile (mind you, these are my first impressions).
Louis Litt: Junior partner at the firm & envious of Harvey. Isn't afraid to fight dirty (in a clean way).
Jessica Pearson: The cocky, overbearing managing partner of the law firm Pearson Hardman
Harvey Spectre: Senior partner at the firm and best closer in New York...and he knows it.
Mike Ross: Associate attorney w/ a photographic memory. He never attended law school.
Rachel Zane: Paralegal struggling to become a lawyer. Develops feelings for Mike.
Donna Paulsen: Harvey's secretary, friend, and confidant. And they do this 'thing' with a can opener.
Every episode these character grow in such a dynamic way that my overall opinion of them and their relationship with one another changes. Characters that I consider heroes fall, and characters I utterly loathe (Lewis, I'm looking at you) grow on me.
A lot of stories can be described as 'good' vs 'evil'.
Personally, I've always disliked characters who are good for the sake of being good, or evil for the sake of being evil. People are the heroes of their own story. We have a psychological need to think well of ourselves. It's called ego justification. Every story, IMO, should have a protagonist and antagonist who can successfully convince a reader that their actions are justified.
Abortion, NSA homeland spying, or the Treyvon Martin case are all great examples. Equipped with an open mind, I think anyone could say "I understand why you believe that, but I feel...."
I recently rewrote a scene in Black Sheep from another character's POV. Initially, my MC was made to look like the hero, but after the rewrite, you realize she was being an ass. If you rewrote your story from you protagonist's POV, would he/she/it still be the antagonist? (That isn't a rhetorical question. I'd like to know)
In Suits, each character does what's necessary to preserve their professional and personal relationship with one another. Sometimes both can't be satisfied. At those times, you see the job overshadow conscience. Good characters do bad things for a good reason. I believe these kinds of characters show more depth and are more engaging and realistic than characters who always do the good and right thing. Or always do the bad and wrong thing.