Fun is Necessary

I think that fun is essential to productivity and happiness in work.  But I often wonder why even a 'fun' job might seem like drudgery at times?

I wonder if there's some kind of boredom quotient that artists get used to that sets our boredom levels? I actually feel hugely guilty to think I might complain about a job being boring when I consider the awful jobs many people have to endure.

I suppose it's the child within that demands fun... while the tired grownup on the outside gets philosophical and wags a finger of rebuke.