Wisdom comes from experience. So in creating characters that we can identify with, there are a lot of things to consider. We identify with people who are like us. The more they are like us, the more strongly we identify. If they are different from us, then we have to consider how that difference is going to affect how people identify with the character.
Difference is intriguing.
Villains are typically evil and like it. But villains who show some humanity can also make the story more interesting. Authority figures must not be too perfect but must not make a big demonstration of their failings. Put a strong good character and a strong evil character in the same movie and you have high concept and people love it. Most other characters must be human, and struggling with being human.