The daily time slot
in which you must have some form of caffeine otherwise you will
get a headache. No amount of caffeine after this window will
cure the headache. A common ailment of coffee addicts who need their morning fix before they can function
Dude1: Fuck, I've missed my caffeine window, I feel a headache developing.
Dude2: Rookie error dude, that's you should always
keep a few No-Doze handy when you don't have time
to grab some coffee.