"In wine the truth".
Do you think that people show their true colors when they're drunk? Not dinner-party buzzed - OBLITERATED. To the point where your friends have to gently break it to you what you did last night...
Does alcohol cut through socially programmed facades, behaviors and preferences, leaving only the raw essence of self to interact with the world?
For instance, a violent drunk = a generally angry person who just deeply suppresses it in daily sober life, or channels it in more innocuous ways. A talkative drunk = a true extrovert, who might seem introverted due to anxiety and/or intense self-regulation ("pfft! Only morons go around yammering about!")
Taking it a step further, do you think that the actions done only when drunk are actions that the same person sober has the URGE to do, but doesn't let himself?