Using undocumented code is like programming in a language I hate. Mentally it's a really shitty experience and I'm not in a position where I have to settle for that. If I needed to do it to put food on the table, obviously I would.
You're also creating this false dichotomy between getting stuff done and documenting your code. I've never been in a position to have to choose between the two. If you have time to write a good program but not enough time to document it, I would question whether the program you wrote is actually good. If I'm writing a paper, sure I can spew shit out on a page for a couple hours and produce a "paper". But realistically if I'm actually going to produce a paper I need time for outlining and proofreading.
(Note that "documentation" isn't really what matters, it's that the code is understandable. If the code is self-documenting or the program is small enough, I consider that documented code.)