ME TOO! I will play "Ain't She Sweet" as learned from Jim Beloff's "The Daily Ukulele" at a breakneck speed, like 160bpm. This is one of the few songs that I can play fast and not mess up.
(something like this - but MUCH faster now)
Usually the response is either an open jaw, or one word: "Typical" (ha ha)
and then they ask, "Can't you play
anything else?" and then I will break out the first 16 bars of Jake's "Piano Forte", after which I will stop (since that's all I've learned so far, but THEY don't know that) and then SMILE and ask them, 'What can YOU play?' and offer them the instrument, after which most people will decline, or say that they do not know how to play, but would like to learn, and then I tell them about Ukulele Underground and the video tutorials, and also the community in the forums.