You have probably been to a social function where certain guests feel confident about their ability to drive despite having had a few drinks. One of the reasons for this is that everyone reacts to alcohol differently depending on their physiological makeup. While one person may not appear to be affected by having a glass of wine, someone else may feel dizzy or giddy and become sleepy or overly talkative. It only takes a few drinks to exceed the legal limit of 0.08 percent blood-alcohol content (BAC), but many experts feel there is cause for the legal threshold to be lowered.