No, sorry. Nice isn't the word. Lubricated and talky, blubbering and nostalgic, like a character out of Russian play or novel, maybe. But haven't meant anyone that drunkeness improves on a consistent basis.
The reason your argument is invalid is that most people don't go through life trying to hide their good points; thus, they don't slip out only when someone is drunk or otherwise off guard.
A desire to be sociable, suppressed by shyness or fear of missteps, is about the only exception I can think of.