I have never think about being a private investigator. This is a job that doesn't attrack my attention. Perhaps it is interesting, but I think sometimes it can be dangerous depending on the subject of the investigation.
I have never needed the services of a private investigator. And I hope not to need them!
I have always worked in jobs related to my studies (librarianship) so they haven't been strage and they are interesting if you are interested in this subject.