I have fond childhood memories of the 2003 blackout in NYC[1]. Few cars were driving around because traffic lights were off and intersections became all-way stops. It was around ~90 degrees so food was going to spoil very quickly unrefrigerated.

The surprising thing that happened next was that people started up impromptu block parties with people pitching in ice cream and all the meat they had in their fridges for BBQs in the streets!

Being city folks, you don't really trust your neighbors let alone talk to them. But I got to meet a lot of them that day and it turns out people aren't that scary and are very willing to help one another in times of need.

[1]: https://en.wikipedia.org/wiki/Northeast_blackout_of_2003