I've had a small pot of St. Michael's Earl Grey tea, because otherwise I would be kicking people in the groin and taking surly naps under my desk. Caffeine makes me more alert and energetic, to be sure, but it also makes me paranoid and twitchy. And I'm normally paranoid enough that I don't like sitting with my back to a door. This level of alertness isn't healthy.
Also, caffeine is not good for my blood pressure. I can feel the blood racing through the veins and arteries in my hands as I write this. It's like an itch inside my veins.
W*rk owes me a day off, and soon. If they don't give it to me this week, I will in all likelihood maim or kill someone. And get away with it.