Walk into an office, and the person behind the desk begins an interaction.

You respond (or react). They respond (or react) in turn.

Answer the phone. Caller ID tells you who it is–are you smiling? How much enthusiasm or disdain or annoyance or delight comes through?

The caller responds (or reacts). And so it goes.

Every interaction leads to the next interaction.

But the first one starts the whole thing. And that one can be up to us.