An improvement in my opinion would be to set an approximate break time and then lock you out around that time when your behavior switches -- I'd imagine that ha

An improvement in my opinion would be to set an approximate break time and then lock you out around that time when your behavior switches -- I'd imagine that having your screen lock when you're in the zone solving a complex problem would be as bad as someone interrupting you. It would be pretty easy to find my natural break times by seeing when I open gmail and hackernews or when I create a commit. I'd probably benefit a lot from a walk instead of surfing around the internet for 15 minutes as a break. I hate being interrupted while I'm working though -- this would infuriate me as much as a knock on my closed door for a question that could have been emailed.