I think I met the Upstairs Neighbors this evening. They were climbing the stairs, I was coming out my front door, and when we met on the landing, I realized instantly who they must be and blurted out "HI!!!" in a very loud, overly bright voice. The woman -- a pretty, professional-looking blonde, perhaps a few years younger than me -- smiled and said "Hi" in return, only much more calmly. And I clamped my mouth shut and hurried down to my car, because the first thing that had popped into my head was Monty Python, and I was having to restrain the urge to shout "Is she a goer? Does she go? Oh, say no MORE!" after the man's retreating back.
I can tell already that I will never be able to behave normally around these perfectly pleasant people. Ever. *facepalm*