On my weekend walk-run on the Mall, I practice a bit of patriotic profiling. It always happens around the National World War II Memorial. He’s usually bent with age or in a wheel chair pushed by a younger relative. A daughter or a grandson, perhaps. And he’s usually wearing a cap or T-shirt that lets you know he’s a veteran of a particular unit or ship or battle. He is a member of the Greatest Generation and he’s disappearing.

Being a sentimental soul, seeing those men moves me in ways I can’t describe. My mind swirls with questions: What role did they play in the war or the war effort? What must their sacrifices have been? What horrors did they see? What were their lives like in the years since? That’s why, when I have the strength, I will pick one as I dash by and say, “Thank you, sir!”

I catch only a glimpse of their surprise or gratitude or smile because I don’t stop. I don’t look back. I can’t. Just saying the words sends a chill up my spine and brings tears of gratitude to my eyes. And it happened again yesterday, yet in an unexpected place and with an unexpected person.

The White House was inching closer as I race-walked my way through Lafayette Park. When I saw him, I was taking stock of how my life had changed in the 10 years since a beautiful day in New York City turned ugly. A young man in what looked like dress whites crossing into the park from Pennsylvania Avenue with a woman who had to have been his mother. As I passed them, I looked him in the eye and said, “Thank you!” I caught a glimpse of his surprise and the start of a smile. But I didn’t stop. I didn’t look back. I couldn’t.

Discussing how much things have changed for America since Sept. 11, 2001, President Obama told NBC Nightly News anchor Brian Williams, “[W]hat I’m struck by is how much continuity there is.” In the interview that aired yesterday, he continued, “There are folks who are still working in office buildings in Manhattan. New York is still this incredibly vibrant, dynamic place full of diversity. Immigrants are still pouring in from all around the world because they want that piece of the American Dream.”

And there are still men and women willing to serve their country. Even those who didn’t really know what evil was until Sept. 11, 2001, but who think nothing of protecting the nation from it today. Without reservation. And more often than not, without a thank-you from a grateful public.