On my last day of work before moving to Argentina from Washington, DC I walked into the metro and passed by a blind homeless man that stood in the same spot almost every day for a year. I walked right by him and said, "sorry, next time," knowing there was not going to be a next time.
At the bottom of the first set of escalators, I stopped, looked into my wallet and saw a \$20 bill. I thought, what the hell, I don't need it. I turned around, walked back up the escalator and as I was approaching the blind man, I saw a woman walking toward in his direction right behind me. I put my \$20 into his cup and the woman dropped in a bill as well.
I went back down the escalators and while waiting for my train the same woman walked up to me, "What made you turn around and put \$20 in his cup?"
"It's his day I guess."
She looks at me and tells me that she did the exact same thing; walked past the blind man, turned around and put \$20 in his cup. The two of us did this in tandem without know we were doing it until we dropped the money in his cup.
I can't explain what happened but it sent chills down my spine, I have a feeling the man really needed that money that day.