I tell you what though, as David mentioned above, there is no better way to spark up a conversation with a stranger than to be working on your car outside.
I sometimes get people talking to me while working on my cars, but usually "care in the community" types. Usually very chatty and friendly people but def not all there. There was one bloke who insisted where a certain wire in my engine bay should go and when i politely said i didn't agree he called me a bald c**t, gave me a menacing look and stormed off nearly getting himself run over in the process. Luckily i've not seen him again.