There is a custom in Naples, Italy where people buy two coffees—one for themselves and one for a stranger. Why?

It is said that the custom of caffé sospeso was started over 100 years ago in Naples, Italy. When translated, it means ‘pending’ or ‘suspended’ coffee. The tradition began in working class coffee houses. If someone was fortunate enough to experience some good fortune, they would order two cups of coffee, but would only drink one. A less fortunate person inquiring if there was a sospeso available would then be served a free cup of coffee.

Coffee shops in other countries adopted the tradition to increase their coffee sales. It is practiced in Bulgaria, Ukraine, Australia, Canada, Russia, Spain, Argentina, the United States and Costa Rica. On 22 July 2013 an anonymous customer bought 500 large sospesos at a well known Canadian coffee chain!

The idea of caffé sospeso has become a symbol of social solidarity, and the 2008 recession and the Eurozone crisis has prompted it's revival worldwide. In 2013 Starbucks UK said it would match the price of every suspended coffee with a donation to Oasis charity. This charity’s aim is to deliver housing, education, training, youth work and healthcare to homeless young people.

Although it has been reported that the custom has almost become obsolete in the country of it's origin, it seems that the global financial crisis has sparked a new wave of social solidarity that prompted the come-back of the kindness of the caffé sospeso.

(Source)