It has taken me a while to realize something.

Seventeen years ago, I saw a picture of Mohamed Atta for the first time, and my blood boiled from the sound of his voice emanating from the television, as he said over the airplane’s intercom system: “We have some planes, just stay quiet and you’ll be O.K. We are returning to the airport.” Instead, he crashed it between the 93rd and 99th floors of the World Trade Center’s north tower.

My 23-year-old brother, James, was on the 102nd floor.

Staring at that picture of Atta, I would have visions of what my brother’s final moments were like. I would envision my asthmatic brother slowly succumbing to smoke inhalation on the flat, gray corporate rug of his Cantor Fitzgerald office — trapped, climbing upward and afraid for the entire 102 minutes before the tower’s collapse. Glaring at Atta’s photo, I’d imagine my brother’s body buckling, falling, crumpling, burning, melting, and in that moment of imagination, my entire being wanted revenge against the people who did this.

So I joined the Army.

I joined the war. I deployed twice to Iraq and once to Afghanistan.

I learned many things but realized just one.

I learned that deploying for the second time was easier than the first, but each time it’s harder to fully come home.