A psychology professor once asked a class why they were taking a psychology course. Their responses give the range of reasons that people want to learn about psychology:

To understand themselves

To understand other people and groups

To be better able to influence others, for example, in socializing children or motivating employees

To learn how to better help others and improve the world, for example, by doing effective psychotherapy

To learn a skill that will lead to a profession such as being a social worker or a professor

To learn how to evaluate the research claims you hear or read about

Because it is interesting, challenging, and fun!

People want to learn about psychology because this is exciting in itself, regardless of other positive outcomes it might have. Why do we see movies? Because they are fun and exciting, and we need no other reason. Thus, one good reason to study psychology is that it can be rewarding in itself.