I was watching (or rather, listening to) a YouTube recording of At The Movies by Roger Ebert and Gene Siskel. It was their "worst of the year" compilation, and at one point Gene Siskel asks Roger Ebert if he remembers the picture cutting out at the press screening of The Nutcracker Prince. Neither of them made any move to tell the projectionist, as they reckoned it was at least as good that way.
I felt a powerful frisson of pleasure at this anecdote-- I love any kind of shared experience, shared memory. Something that happened and is unrepeatable, that was shared by two or more people but can never be shared by anyone else. There's something delicious about it. But so hard to explain!