Teenagers should obey their parents because they have more experience than teenagers have. So, parents tend to know what's good and bad for us.

Parents are able to teach teenagers responsibility. Responsibility is a very important key for working, living on your own, etc. Hence, teenagers grow up with regulations set from parents like chores. They won't able to learn responsibility if they disobey their parents.

When teenagers don't obey their parents. they wil tend to feel that they have more control than their parents. When this happens, teenagers will become disobedient and will challenge with their parents which can lead to a lot of conflict.