I enjoyed an article in INC Magazine recently titled, “How Hard Could It Be?: Five Easy Ways to Fail” by Joel Spolsky – The article mentioned five reasons technology projects go wrong. In line with the message of Juggling Elephants was Mistake No. 5: Work till midnight. Some highlights from the article are:

“There's a whole body of literature establishing that working more hours doesn't produce software any faster. Edward Yourdon, the software entrepreneur and author, dubbed this kind of project the ‘death march.’”
“Software development takes immense intellectual effort. Even the best programmers can rarely sustain that level of effort for more than a few hours a day. Beyond that, they need to rest their brains a bit.”
“Compelling employees to spend even more hours sitting in front of a computer won't really translate into more output--or if it does, it will be the wrong kind of output.”
“Running a death march is not the only way to make a project late and a budget buster. But it is a surefire way to do so.”

I think the same concepts apply to “non-programmers” as well. A lot of times we feel that if we work longer hours we will be more productive and get more done. The reality is that the law of diminishing returns applies. We need to take daily intermissions and “rest our brains a bit”. We need to maintain a good performance in all the rings of our life. A good, focused, 8 hour day will deliver better results in the long run.