It happened to me. The guy working under me, for five years or more, moved to a different job in the company and drew level with me. He came back into the department at a higher level than me but not directly in charge of me. Then the sections within the department were re-organised and he became my boss. I always tried to treat him with respect and he returned the favour when the roles were reversed. We always worked well together and, no matter who was in charge, we made a great team.

As for retirement, at the time of writing this, I have 29 days 9 hours and 41 minutes to go. Not that I'm counting, of course.