It's when I'm away from Japan and forced to speak in another language (in this case English) that I realize just how vague Japanese can get. At home, it's possible to go through a whole day without uttering one coherent sentence built on spontaneous thought and logic.
The basic aisatsu (salutations) will get me through, and apart from that I can trot out meaningless but all-important rejoinders such as domo and iya, which fits nicely in almost any situation. Instead of saying, "Thank you, how thoughtful of you to take the time," I can just bow deeply and proffer a heartfelt domo.
When I'm trying to get out of a social engagement, I can just tilt my head to one side and say iya with a smile. Believe me, when you're an antisocial crank, the existence of such rejoinders makes life infinitely more convenient. Deprived of them, I find myself painfully aware of my awkwardness and groping for the right things to say.