Imagine starting at 8 and finishing at 1. Working well at a Shart Tank company. And I have increasingly started hearing/reading about this on CBC and Harvard Business Review (HBR).
Productive hours in a day are around 5 anyways, the sources claim. Rest is filled with chatter, eating, face-book, youtube etc. I have even seen people playing video games in the afternoon, OPENLY! :-)
So, how this works is if the work done is measured by goals not time. If you slack, you go!!! Not for everyone. What are you going to do with rest of the time. Whatever you like. Spending time with kids in a park or doing creative work, which happen to be entrepreneurial interests in my case.