Eli Bendersky's website You have some problem to handle at work. Some code to write, some bug to fix, some new feature implement, whatever. You have a nice idea on how to do it, and fall into hacking-mood, just spilling nice code and finishing the task in a day or two (those day or two of hacker happiness, when you look at the clock and it's 2 PM, and next time you look is 9 PM). Then you think - geezers, I finished this task so quickly, wow.
But then, you find out that since it's not just a hack for pleasure, but a work thing, there are a lot more to handle. Little quirks here and there, testbases fail - fix those little things, etc. Document diligently, test for backward compatibility, bla bla bla, another two weeks spent just tailoring it all to work with the project.
Ahh... maybe that's why people go and turn into "software architects" and "designers", leaving all the fix-up work to students, interns and Indians/Romanians :-) But I would still miss the coding...