Personality Problems
There are often personality conflicts in the office, even between "two decent, mentally healthy people" - and it's a particular problem when the person with whom you clash is your supervisor.
Ideally, personality conflicts are something that can be avoided during the interview process: the personality of your supervisor is something worth considering when you decide whether to accept a job.
However, there are a number of situations where you have a boss whose not of your choosing, and you have to rough it out: interpret their personality traits and do what you can to get along with them until you can find another situation.
EN: None of this is useful advice - seek other sources for dealing with problem individuals.