From the Here's Why I'm Not A Superhero File:
Years ago, I was walking east on East Capitol Street -- almost literally within the shadow of the dome of the Capitol Buidling -- when I spotted a woman about block in front of me running frantically in my direction, chasing after a large golden retriever. The dog was running at full speed, its leash trailing along behind it, visibly delighted in that Whoopee! I'm A Dog On The Loose! way.
Because I'm always willing to help, I stepped over into the grass on the lawn of the Library of Congress to put down my shoulder bag, then moved back onto the sidewalk in a wide stance, bracing myself to take the full impact of the speeding golden retriever, hoping to stop it from its flight of fancy and earning, I was certain, the gratitude of the damsel in distress who was chasing after it.
As the dog careened toward me, I grit my teeth and, with an atypically-elegant move, all at once snagged the leash and shouted "Whoa!" at the dog. The dog pulled up short, ears up and alert, staring at me with a hurt look that all but screamed Why would you DO that?. I stood there with the leash in my hand, waiting to hand the dog over to the running woman . . .
. . . and she jogged right past me, frowning. With a short whistle, she called the dog back over, and the two of them turned left across the front of the Library of Congress, continuing on their evening jog, which had been only briefly interrupted by the Crazy Guy in the Suit Who Had Jumped At Her Dog.