Street singing Dead Heads

So i was walking to the post office to drop off some letters; when this old dead head starting singing to me "Livin on Reds, Vitamin C and Cocaaaaaine". He was confused and thought my Vatican Tattoo Shirt said Grateful dead lol. I would of joined in with him but i didnt know the full song. A random stranger singing to me is pretty awesome; but one upping him by singing the rest of the song in an impromptu duet would of been a spectacular moment in buffoonery.