i agree with this. as i've gotten older i've become a morning person, usually starting around 6, but sometimes earlier. you can easily belt out 4-5 hours of real work before lunch time, and then take a leisurely lunch/walk/coffee, and do administrative / non-intense tasks in the early afternoon, leaving a relaxed afternoon and evening to do real life things.

and, when a true emergency pops up, it's rare, and it doesn't trigger your stress/frustration response.