I recently read the commencement address that Bill Waterson (creator of Calvin and Hobbes) gave at Kenyon, and the story he told about recreating Michelangelo's Sistine Chapel painting stuck out to me. After completing the project, he finally asked for permission to do it, but was rejected and had to paint over it. Waterson writes:
Despite the futility of the whole episode, my fondest memories of college are times like these, where things were done out of some inexplicable inner imperative, rather than because the work was demanded. Clearly, I never spent as much time or work on any authorized art project, or any poli sci paper, as I spent on this one act of vandalism.
The sense of joy he found in pursuing that "inexplicable inner imperative" is prevalent throughout Calvin and Hobbes, particularly in Calvin's infinite appetite for building elaborate snow sculptures. I suspect the zealousness with which he commits to making those snowmen (despite their inevitable demise once the temperature rises) resonates with a lot of creators.
The process of creating something is often just as important as the final product. This is in part because the time and effort required to make something truly extraordinary isn't justified by what you've accomplished. As such, it's important to listen to those inner imperatives.