A word about lack of sleep: It is not good.
I was napping away in the office when one of my colleagues decided to come back from lunch. I snapped awake at the sound of the keypad, and I think all that snapping awake has given me a headache. You try going from asleep to wide awake in a split-second. It's a bit disorientating, and I bet somewhere along the way, the brains shifted a little inside the skull. It's like one moment the head's in a reclined position, then less than a second later it's upright. The brains, which are still asleep, probably got left behind in the reclined position as sitting upright was a natural reaction to the sound of the keypad. One of these days, I'm going to get my brains turned upside down.