My jc girlfriend and I are highly susceptible to caffeine.
We both drank coffee unwittingly yesterday just after 6pm.
I stayed awake till 2 and craved running.
She stayed awake till 3, and got up to drink half a can of beer to neutralise the caffeine so that she could sleep.

The only good side (if any) is I've thought previously that caffeine can keep me awake for 12 hour cycles, and it's actually only 8 hours this time. lol. Surely I've improved!