As we exited the parking lot, my husband slowed the car to wait for a young woman riding her bike. When Tom nodded to indicate she could go first, she smiled, waved, and rode on. Moments later, the driver from a parked SUV threw his door open, knocking the young bicyclist to the pavement. Her legs bleeding, she cried as she examined her bent-up bike.

My training for the long-distance race was going badly, and the latest run was particularly disappointing. I walked half the time and even had to sit down at one point. It felt like I had failed a mini-test.

I scanned the water intently, on alert for signs of trouble. During my six-hour shifts as a lifeguard, I watched from the side of the pool to ensure the safety of those swimming. Leaving my post, or even becoming lax in my attentiveness, could have grave consequences for those in the pool. If a swimmer was in danger of drowning due to injury or lack of skill, it was my responsibility to pluck them from the water and return them to safety on the pool deck.