If you love what you are doing, spending hours on hours "geeking out" is fun, not work.
This becomes an issue when there are situations created that force you to work ridiculous hours. As an example, at a previous position, the boss waved the "we get so much done with so few resources" flag on a daily basis.
What he failed to understand was what was getting done was a series of hacks, patches, cracks, and workarounds that were holding the system together. The end users didn't know any better, so everyone was happy. There was no time to innovate, analyze, plan, or prepare.