Work and Satisfaction

Your satisfaction must come from the high you get when you suddenly, for the first time understand the problem you are working on and see your way to a solution. I use the word “high” advisedly. You need to be something like an addict for this feeling to provide sufficient recompense for all that work.

From Ian Stewart in “Letters to a Young Mathematician” in the chapter on “The Career Ladder”.

Also:

Definition of Work