In Japanese business culture, being in one's cups is a socially acceptable excuse for saying virtually anything, regardless of e.g. relative social status or non-desirability of the message. Accordingly, many of the really important messages internally and externally are passed after hours with a beer in hand. (Incidentally, people will even treat you as being drunk even if you're only sipping coke, because it is mutually socially important that you be seen as being drunk. I mean, after all, you couldn't possibly verbalized that complaint to your boss while being sober, right? So clearly you're drunk.)