At my job, I used to stay late. I'd stay until 10 PM some nights and be super productive. Except I realized that I was dicking around until 5 PM and then being super productive for five hours after most (non-tech) people had gone home. I was staying up late, waking up late, being useless for most of the morning, taking long lunches, and not getting much done.
Now I get up every morning, I get to work around 8:30. I spend about an hour in the morning getting my work sorted out, getting my head together, figuring out my tasks for the day, and then being productive until 5 PM, then leaving. I've been more productive, I've been more accessible to coworkers with different schedules, I'm enjoying my job more, and more importantly, I'm enjoying life more. I'm not tired all day, I'm not useless when I get home, I'm not up late for no good reason.
Working a fixed, reasonable schedule (with occasional exceptions) has been such a huge boost to my productivity that even people I don't work directly with have commented to my manager on how much of a difference it's made.
The hardest part, as she mentions in her talk, is leaving even though my manager is still here, and still working on things, but when I realized that I stopped being very productive at about 4:30 anyway, I figured that was a good reason to tap out and go home.
Try it. It works.