Eric Liu: I think there's three problems with cell phones, they start with the letter P. When you look at a bright screen within an hour of bedtime, you don't produce as much melatonin,. Blame your pineal gland for that one. If you like me, ever turn your phone off right before going to bed, don't you feel like it's time to get the caves set up and build a fire? That's what it probably is in us. There's a huge, huge physical issue. And then the third one is productivity. We all know what hooks us now. Some reports are saying it's 31% of our time now now bookmarking and priorit