It's terrible but to really dig in and work I do it best overnight. I just seem to work better with zero risk of interuption. Must have written 3000 lines of new code for a new feature this week (not that lines of code is a good metric but my fingers have been FLYING :))
@scottgal as long as that disciplined action is based on disciplined thought you are probably doing the right thing. My failure sometimes was coding through the night with less rigorous thought discipline then was needed and then had more rework later.