A Breeze From Getting Things Done

When you through a pebble into a puddle of water, how does the water react? The answer, completely appropriately to the mass of the pebble and the force with which it was thrown. The water doesn't over or under react, but when we encounter stressful events in life we often let them control us by provoking a reaction that is disproportionate to what is required. For instance, if you're already buried under a mountain of tasks and then an email comes in adding one more thing, you might feel overwhelmed and respond brusquely, but wouldn't be great if you had a state of mind like water? Not over or under reacting to the email or any other events you encounter, but always just respond appropriately?