Kristen Lamb walks us through the steps of a solid novel (or similar longer project), by breaking down what makes a good leading character. In her analysis, it comes down to giving them relatable flaws. It's one of those things that seems pretty obvious once someone points it out to us, but it's in the pointing out that we work out why:
Perfect people are boring and unlikable and they lack any room to grow. Perfect characters are no different. New writers are often insecure and our protagonists are us…well, the perfect version of us anyway. Our heroines are tall and thin and speak ten languages and have genius IQs and save whales in their free time…and no one likes them.
If we make characters too perfect, readers will revel in their destruction. If we didn’t like tearing down “the beautiful people” then Star Magazine and The Inquirer would have folded decades ago.