Also related, I had a psychology teacher with a PhD in psychology. But because in German schools, you need to teach two subjects (with the exception of the arts), he also taught physics. He was a terrible physics teacher, but a pretty good psychology one.

That reminds me of a story my bachelor’s supervisor in astrophysics told me: One of his best PhDs applied at an insurance company. They got an Excel sheet with data that they had 1 week to analyze. All the other applicants took the whole week. He just put it in Python, solved it in a few hours, and got the job.