|Chigurh From No Country for Old Men|
Protagonists, especially those of the heroic breed, are bound by rules and common perceptions that somewhat inhibit creativity. Antagonists, on the other hand, are wide open for manipulation. They can be bad to the bone like Hannibal Lector or Chigurh. They can be nasty or evil, but mend their wayward ways like Ebenezer Scrooge or Darth Vader. The reader may be misdirected to believe the antagonist is bad and then everything is turned around like with Boo Radley and Mr. Darcy. Antagonists can make a story memorable, even when the antagonist isn't even human— like Moby Dick or Christine. The one thing these antagonists all have in common is great character development.
Your concentration on character development shouldn't even stop with the protagonist and antagonist. Nobody willingly hangs around boring people and nobody wants to read about characters with cornmeal personalities, not even bit players. Everybody inside the covers of your book has to be interesting. Give each of them a distinct personality. If you have a character like a postman or waitress that only appears for a couple pages, don't describe their personality, show it. You need to do it with dress, movement, or dialogue. Show, don't tell, is more difficult with the brevity of a minor player, but you only need to spice the character enough to make him or her three dimensional.
Here's an example from my novel, The Shopkeeper.
I asked the hotel clerk for the best lawyer in town. He directed me to a man named Jansen who had an office across from the Capital building. I then asked to see the chambermaid in my room so I could give her some special instruction. After a brief wait, an exceptionally skinny girl arrived whose cheap dress fell straight down from her narrow shoulders.
“You sent for me?” she asked.
“I would like you to do me a favor. I’ll pay handsomely.”
“I haven’t told you what I want yet.”
“Tell me … and then I'll tell you what handsomely means.”
That took me aback, but I plunged ahead. “I want you to write a letter and sign it with another woman’s name. Can you write?”
“You mean can I forge?”