Which, of course, begs the question: just what is keeping you awake, then?

My hypothesis is that the brain and body are lazy. You ingest caffeinated beverages for a while; they get used to responding in a certain way. You start ingesting otherwise-identical decaffeinated beverages instead, and they respond in the same way because they’re too lazy to check whether there’s actually caffeine there or not.

Yeah, it’s not scientific… but there is a large body of evidence to support it. 🙂

(Via LifeHacker.)