In the movie, we see how Marlin changes after the death of his wife. His anxiety about protecting Nemo overpowers his ability to actively listen and trust his son. This pushes Nemo to be outwardly defiant towards his father.
As parents, our past influences how we deal with our kids. If we step back and change our approach, we may find that our children’s behavior changes too.
Read more about this in “4 Lessons Finding Nemo Taught Me About Parenting” here