I contribute to the economy. My dentist likes seeing me. My ENT doc likes seeing me. Regular doctors like helping. My boss's boss's boss's boss is probably aware that stuff gets done. There are lots of layers in society. I am but a pebble. My contributions may be small in the grand scheme of things, but it takes many small contributions for the world to function.
Life presents many opportunities for decisions to be made. And when one makes decisions, you (and I) are contributing to the fabric that is life. We add to the story, the song.