> 3. Learn how to manage other people so they do the work for you. Learning psychology will also pay it back here. If you master psychology, people will be able to do things under your management that they are not able to do on their own.

I hope you're referring to cases where you're a project lead or in a position of management. Because if not, tread with care as most people can be easily influenced but if you run into another person who 'masters psychology' you may end up having a really bad time.