Will that ink black cup of coffee really get you on the straight and narrow after you've seen the bottom of a few too many shots of Patron? Or is your daily cup of joe really dehydrating you while perking you up? WebMD examined 8 different common beliefs about caffeine and compared them against available studies to determine if they were fact or fiction. If you're wondering if you're working under any misconceptions about the brew, check out their opinions. Oh, and that sobering up bit? Sorry...no: Actually, research suggests that people only think caffeine helps them sober up. For example, people who drink caffeine along with alcohol think they're OK behind the wheel. But the truth is reaction time and judgment are still impaired. College kids who drink both alcohol and caffeine are actually more likely to have car accidents.