I wish I knew the answer to this. When everything is totally screwed up and on fire and I need to get something done by 5:00 today that would normally take a week and a half, by God, it becomes apparent every millimeter of fat that can be trimmed and I can usually scrape together what's needed by then. Then the deadline is over and I get a similar project the next day and it's back to taking 5 days to finish.

There are real quality differences between the two scenarios, but they aren't nearly as bad as what you'd think they are. The reality is that I can just work a lot more efficiently when stressed. If I could do that all the time I'd be able to work 3 hours a day and remain as productive.