The Mythical Man-Month is a great book not only because of its insights about software projects. Fred Brooks also writes about the "The Joys of the Craft":

Why is programming fun? What delights may its practitioner expects as his reward? The first is the sheer joy of making things. [...] Second is the pleasure of making things that are useful to other people. [...] Third is the fascination of fashioning complex puzzle-like objects of interlocking moving parts and watching them work in subtle cycles, playing out the consequences of principles built in from the beginning. [...] Fourth is the joy of always learning, which springs from the non repeating nature of the task. [...] Finally, there is the delight of working in such a tractable medium. The programmer, like the poet, works only slightly removed from pure thought-stuff.

Really worth the reading.