the worth of a smile

I managed to gather all strength and ask a mother of a pre-schooler whether she'd be up for her son having a play date with Alex.
Doesn't sound like much to you I am sure, but for me to ask, was a risk in experiencing a multitude of humiliated rejection scenarios.
In response to my surprising question, the mother's mouth formed a positive arc, her eyes lit up and her posture appeared to express relief. "Yes", came the resounding reply. "He would LOVE that".
Well releif was found in both sides of the conversation. Her smile was a blessing to my heart - a connection, at last. So what is the worth of a smile? My parents might say "too much" - they had to fork out hideous amounts of cash for orthodontics for two dentally challenged kids, but for me, in this situation- well it was priceless.