We've all been there ... You get wasted with some friends, people you fancy, or w.e .. and something is said or done which would never have been said or done under sober circumstances.... Do you believe that it's the 'alcohol talking' and nothing more, or the fact that they were drunk just made it easier to reveal their true outlooks/feelings?

Because your brain is a machine that works hard to keep itself balanced and well lubricated. When you drink, it puts stress on the brain (alcohol is a depressant) which results in the brain having to work to compensate to stay in balance. (like how you put your hands out when you're about to trip) The simplest answer to what you're asking is that different people have their brains wired in different ways. Alcohol doesn't directly produce any emotion, rather it impairs the brains ability to regular emotions, so certain behaviors become more dominant than they normally would be.