I beleive railroading is the only industry I know of the actively dislikes it's supporters and frowns on them becoming involved professionally. I will readily admit being a "railfan". I love railroading. Period. I've loved it all my life, I have an interest in all aspects of it. Does having this interest make me a better employee? Probably. I see my fellow workers, making comments about "foamers" and laughing at me when I wave to someone with a camera. That attitude is pure BS, and I make a point to tell them that.
How many airline pilots do it because "its a job"? I would venture a guess that these guys have loved to fly all thier lives. They took thier passion and made it thier carrier. I'm sure there are other professions that the same way. There are goofy fans of every avocation, just as there are serious ones. It's really OK to like your job, just don't stop in the middle of something important to take a pic of that rare engine that just went past.