I don't think that's necessarily true though. You might say something while drunk that you wouldn't think in the same situation while sober.
Meaning drunken behavior reveals more about a person than sober behavior.
I agree that you can act more truthfully, but that doesn't mean that everything you do or say is what you'd think to say or do while sober.
Alcohol is the solvent of the superego. It strips away social facades and shows people for who they really are, warts and all.
I don't think that's all it does though. I think it can also change emotions to what they might not be normally. Perception is also changed.
If a friend shouts at you, or swears at you, while drunk, I'd say it's totally reasonable to say 'It's okay, you were drunk', not to think they are really a bad person. If they were annoyed beyond what they would be sober, then they might say something they wouldn't normally be inclined to say.
It's a truth serum. It makes it easier to talk and harder to lie, especially harder to lie convincingly.
Is it harder to lie? I'd think it could just as well make it so that you don't care if you lie. On the other hand, if you are really drunk to the point of memory loss, rather than very tipsy, perhaps you don't care about lying any more.
It not so much that they look different; you're just less picky.
I think they actually look different. I know one time I was looking at a guy I knew, and I was trying to see him like I normally do, but I couldn't. I mean... he looked photo-shopped. I even wondered for a second if it was actually him.
Being who you really are isn't about being good or bad. Calling somebody a "#@$*! &@%#" when drunk indicates that you really think that person is a #@$*! &@%. Right or wrong, it's what you think. If you don't talk to people that way to their face when sober, that's a self-censorship mechanism.
I think that ignores that people might be more emotional when drunk. For example, with my ex-bf, after I'd had a few drinks, I tended to want to say 'I love you' (and I was only tipsy). The sad truth is that I didn't think that while sober.
Also, thinking someone is a #@$*!&@% at that moment, is different from thinking they are a #@$*!&@% in general.