I had forgotten how much your hands can shake until I started tagging. I was reminded of when I was working at a research lab and one of the TA's had told me he can't drink coffee because his boss was experimenting on fly vision and he had to insert electrodes into the visual center of the flies' brain and glue them in place.
He said it takes 72 hours for the caffein to be completely metabolized out of your body. 
