When I was six, my family and I got into a car crash and some random woman who lived on the street where it happened let us into her house and gave us hot drinks while we waited for the police etc to come. For years, I thought she was a friend of my parents and we just happened to crash on her road.
And last year, I had a hospital appointment that was supposed to be at 9.30am - come 12.30pm, I'm still in the waiting room stressing because I'd run out of money for parking (it costs like £2 an hour and I never expected to be there that long). Anyway I was chatting to this family and then they got called in for their appointment and on the way in, the dad silently put £2 in my hand and refused to take it back - small gesture but so nice, esp for SE London...