When I first met one of my friends
The reason we got on so well was because she was so used to the conversation dying, and it didn't. It was in one of those interminable university fresher things at a bar, where you say where you grew up, your schools etc.

Her, "Well, I never really went to school because I was in hospital for most of my childhood."
Dead silence, apart from me, who in a tone of delight went, "Ooo, me too! Did yours have a Nintendo? We used to go on missions to liberate it from the infectious disease kids, it was like a Bond film..."

Apparently it wasn't so much that the conversation kept alive after that, it was the fact that I sounded so "disturbingly happy" about the whole thing.
(Sivvus trolley collision in the fruit aisle led to a jam, Fri 13 May 2011, 0:53, Reply)