"8:00pm - Freedom! I usually spend some time in the evenings catching up on email" - I guess Google managers have a slightly different view of freedom from work than I do.
After an evening of chasing kids around the house to get them to eat, wash and sleep, email does feel like freedom. Especially if you like your job. Also, not all email is alike. Usually no one expects you to answer important email in the evening, so you can quietly catch up on stuff you decided to leave out during the day, some mailing lists, etc. It's kinda like reading HN, just more productive.
I find myself using the evenings to catch up on email, because I can take my time and do it in between other things. I'm sure once family life becomes more prevelant I'll change my tune.
I love my (non-Google) job and love my family. So, I'm happy on Fridays when focus changes to family, but I also often love Sunday evenings when focus turns back towards work.
Not everyone has a dreadful, barely tolerable job...