I get nasty withdrawal symptoms if I stop taking caffiene. I've got to have it, because it's so readily accessible to me - if I kick it for a day, I can't help myself, I take a can thinking "well that won't be too bad" and then it's up to 2 glasses of mountain dew & 3 meals a day, plus another liter or so a day.
I'm a failure

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According to that chart, I average over 450mg of caffiene per day, both while I'm away at school, and while I'm at home during the summer. During the summer some days are a lot worse, and I'll climb almost up to 600mg.
EDIT: wiki claims that 400mg is enough for caffiene intoxication, but i beg to differ. i know im addicted, but i dont suffer any of the symptoms they list for intoxication. the only bit i get is sleep disturbances on days where i intake more than average.
Jam it back in, in the dark.