Lack of sleep can affect your reaction times. This is a cute online game that tests how alert you are and also reveals the impact of a cup of tea or coffee on your performance. What was your reaction time? Did it improve after a cup of coffee or tea?
I have not tried this after a cup of coffee or tea. Yet.
Update 1: okay, after one cup of black tea, my reaction times are improving: 0.2042 seconds and counting (down), although I still rank as a bobbing bobcat. Next experiment: coffee.
Update 2: after a decent night’s sleep and one vente iced latte, my reaction times have improved. I am now a rocketing rabbit with 0.1990 seconds as my response time, despite the fact that I am using someone else’s computer that I am quite unfamiliar with.