Deed, indeed!

Producing two 10-rupees bill from my purse, I placed it into his shrivelled, doddering palms. "Nahin aap yeah rak lo" he said vehemently shaking his head. Puzzled I kept insisting with a smile. I was touched.
I had told the cab driver to keep the change. Instead of taking additional six rupees from me he preferred to forego his four. What a soul! My heart went out to that honest, old driver.
I insisted he keep the change and ran away from the scene. Contented and smug, I pondered over the event once more. I was on my way to an interview then. I had supposedly done a good deed.
Yet, something irked my conscience.
Was it unconditional? I couldn't dispel thoughts of an ulterior motive.
There probably lurked in me a latent desire to appease the gods. Would I behave the same way if I was hot, perspiring, late for work and in a foul mood?
Food for thought.