Spike, I'm the same way. Some caffine helps... but too much and I go comatose. It happens to many others and eventually to everyone who gets enough caffine at once. Just depends on who you are before you finally go over the edge with caffine and how much that takes. Just like Alchohol. I can drink that like a fish. Just had my birthday last Friday... yay for being 27. I had so many free drinks I lost count after 25. Yet, I felt the most sober at the end of the night and the bartenders were wondering if I was actually drinking anything or just flushing the drinks down the toilet. LOL, like I'd let booze go to waste like that.
Anyhow, different people are effected differently by stuff. Sometimes you are like the "average" and sometimes you are. I know why Alchohol doesn't affect me much and some other depressants, like Novacaine, Lanocaine, and Vicodin for example. Man it sucks having a metabolism sometimes that is immune to the effects of Vicodin. I got out after surgery once and was in such pain and they gave me that. It took a few more doctor visits to figure out why I was in such pain still even with the medicine.
Oh bleh, sorry got "Off Topic" again. Anyhow, Redbull tastes like crap from crap and then drenched in dog urine. The stuff is horrible.