Everyone, including you and me, justifies actions based on poor reasoning rather than using a spreadsheet for financial decisions. Personal history, unique worldview, ego, pride, marketing, and incentives blend together to form reasoning that may seem crazy to others but creates a coherent narrative for the individual.
The fun part of behavioral finance is learning about how flawed other people can be. The hard part is trying to figure out how flawed you are, and what stories make sense to you but would seem crazy to others.