Julio Diaz has a daily routine. Every night, the 31-year-old social worker ends his hour-long subway commute to the Bronx one stop early, just so he can eat at his favourite diner. But one night last month, as Diaz stepped off the No. 6 train and onto a nearly empty platform, a teenage boy approached and pulled out a knife. Diaz gave the teen his wallet, but as the kid began to walk away he told him, "Hey, wait a minute. You forgot something. If you're going to be robbing people for the rest of the night, you might as well take my coat to keep you warm."