That's definitely true of all work. I am fond of the old saying, "Nobody pays you do what you want to do--only what nobody better is willing to do for less." That saying has always seemed true to me, and I'm always surprised at how even people with "dream jobs" talk about how much they hate it, or at least how large chunks of it aren't satisfying. Take what I do, for instance. Sure it's fun to teach a good group of students, etc., but my "real job" is tediously grading papers, dealing with apathetic or even rebellious students, serving on committees and enduring boring meetings, dealing with drama, etc. However, I have to be thankful for those parts of the job, because they are the reason I was hired. If the job was pure bliss, the pay would suck in proportion to how many better people were willing to do it for less.

I can think of countless other examples. Take lawyers, for instance--they have to deal with the "scum of the earth" on a daily basis. Doctors--do I have to go into detail about the unpleasant things they encounter, or legal threats? Movie stars--constant ego dramas, lack of job security, public scrutiny...Work is work.