Thank you."
For many of us, it is an autonomic response, like breathing or blinking. "Thank you" is a reflex action--a phrase we spurt out at the end of a conversation, mostly to signal its end.
I thank people for calling, for writing, for bagging my groceries, for stopping me on the street to pet my dog. If you are like me, you catch yourself uttering the phrase at least a dozen times each day, but have you ever really stopped to think about what it means?