I don't drink them, largely because everyone I've ever had tasted terrible, like someone pissed in diet pop. I know people who go through at least 3 a day, usually 6, and often as many as 12. Then they wonder why they have trouble waking up in the morning.
Granted, like someone already said, its probably not any worse than many people's coffee habits, but I don't drink either one (mostly because of taste).
I have to give quixtar credit, as when they wanted to get gullible college students into it, they pushed their energy drinks, which was really effective.
Personal story: I worked with a guy that said when he'd drink redbull and vodka he'd get panic attacks. I just kinda said, yeah, that's weird and sucks, but not a big deal just don't drink that. He then proceeded to tell me that he figured he just needed to drink more of them so he'd drink more and it'd get worse. He finally ended up going to the doctor, I think he had a heart murmur, and the drinks would exacerbate it. So, of course he'd still go and drink vodka and redbull. The guy, quite simply was one of the dumbest people I have ever met. Sad thing is he was generally nice, just really stupid. Scary thing is, he was job hunting and two of the places he was being considered for were a defense contractor and the military (although I think it was for accounting).
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