Have you ever watched 'Pay It Forward' the movie, which illustrates paying a good deed to someone after someone paid yours.
I personally came across this concept, when my sister & I were sitting and waiting for our turn after obtaining a ticket number. Ours was '5028', a gentlman came forward and gave us his ticket '5021', becaurse he finished his turn with the help of his friend who had ticktet number '5001', we thanked him.
After waiting for long time my sister noticed a man with bundle of applications, had ticket number '5038', she got up and gave him her old ticket number, i.e. '5028', the man was extreamly greatful and had a pleased smile in his face.
I am greatful for seeing this concept, which I loved it, in action.