What would the Wizard of Oz be without the wizard?
Sure, you don't actually see the wizard (Pay no attention to that man behind the curtain!) until the end, but the whole journey of Dororthy, the Tin Man, the Scarecrow, the Cowardly Lion, and Toto is to meet the wonderful Wizard of Oz. But really, he is a minor character.
What about Tiny Tim in A Christmas Carol? He actually is only mentioned a handful of times and only appears twice - once to utter his famous line, "God bless us everyone!" He, too, is a minor character. But the impact he has on the story is huge.
Minor characters can do lots of things for our novels - they can reveal information, give us background, or set the mood. And they can also be integral to the plot and to our main character's development. Look at how the snotty saleswomen in Pretty Woman affected Julia Roberts' character. They were VERY minor characters, yet they made a big impact on her.
Take a moment to think of your novel or short story. How do your minor characters impact the "bigger picture?"
Just for Fun...
Did you watch Sesame Street as a kid? Do your kids watch it today? I credit that show with helping me learn how to read. And of course, I loved to watch all the Muppets. My favorite one was Grover. But I think my favorite skit is the "One Way" skit. And lo and behold, I found it! The guy can't get to his girlfriend's house because she lives on a one way street. I remember feeling so upset over his plight. How, I wondered, would they ever be together? Yup - an early indication of my future in romance writing. :-) Enjoy.
Sesame Street's One Way Video