Look at the Coen brothers. All their minor characters are as interesting as their protagonists. If the smaller characters are well-written, the whole world of the film becomes enriched. It's not the size of the thing, but the detail.
“When you look at the world, everyone in the world who cares about his or her family wants to have a major portion of their assets in the United States because we are the growth country and the freedom loving country.”
“I make these little films. I'm just a working person. I just study people a little bit more. It's more sociological, and it's funny anyway - not that serious. It's not like false humility. I just take it for what it is.”