I've heard that as well (about blue light), though thankfully I'm apparently immune. I think anything short of looking point-blank at a nuclear blast wouldn't affect me when I'm tired. Same with caffeine and eating. I typically eat and drink a Pepsi just before bed and I sleep like a baby %99 of the time. For me it's more about trying to quiet the chatter in my mind. My brain can sometimes be that one guy at a party who's still up dancing long after everyone else has passed out. Reading before bed helps that.