"In terms of knowledge workers, a programmer produces more good code and fewer bugs when well-rested. We take the first hour or so of the day getting into the groove. The next few hours tend to be our best ones. Later in the day, as we get tired, we get less done per hour — it takes a long time to fix a simple bug or add a simple feature that we would have handled in minutes earlier in the day. Pushed just a little farther — and it seems that much of the computer entertainment industry is working at this extreme most of the time — an overtired IT worker may trash valuable files requiring extra work to restore backups or have an accident on the way home that takes her offline for months."