We are all born with a certain package. We are who we are: where we were born, who we were born as, how we were raised. We're kind of stuck inside that person, and the purpose of civilization and growth is to be able to reach out and empathize a little bit with other people.
If you're not stubborn, you'll give up on experiments too soon. And if you're not flexible, you'll pound your head against the wall and you won't see a different solution to a problem you're trying to solve.