The Guardian Newspaper (London) asks which books would make you stop strangers on the street to share your appreciation?:

This instinct, in even the most reserved of human beings, to stop strangers when they spy one of their most beloved books can even transcend language barriers. As I routed through the dust and flies of a secondhand bookshop in New Delhi, the shopkeeper began wildly gesticulating at the dog-eared copy of Great Expectations in my hand. Then there was the long, hot summer after my A-levels, when I was sprawled in Retiro park, Madrid with a copy of The Waves by Virginia Woolf, and a boy approached to share with me how it had changed his perception of life.

When I worked in a bookstore in Toronto, any time someone bought the Master and the Margarita by Mikhail Bulgakov I always told them how great it was!

Has a total stranger commented on a book you were reading? What book would make you stop someone in the street?