You know how you'd rather douse someone with scalding-hot coffee rather than speak to them before having those first few sips of sweet, sweet brew? But once you're caffeinated, you're all ears? That could be because coffee is just as likely to boost mood as it is alertness. "In addition to blocking adenosine receptors, caffeine also affects other major neurotransmitters, including dopamine, acetylcholine and serotonin, delivering a boost even when we are well-rested," says Clow. "Dopamine improves mood, while serotonin makes us more relaxed, alert and energetic."
The result is a feel-good rush from out morning coffee -- and useful information to those poor unfortunate souls who have ever dared to interact with us before we've had our first cup.