How Caffeine Can Hurt Your Potential for Success -
http://www.entrepreneur.com/article/244079 "Caffeine triggers the release of adrenaline - a hormone which triggers a fast response. This fight-or-flight mechanism is great if you’re being chased by a bear, but not so great when you’re responding to a curt email from an angry customer. When adrenaline is released, your brain is put into a hyper-aroused state, causing you to circumvent rational thinking in favour of a fast response."