Pay a stranger's way

Traveling (airport) and purchased coffee for the gentleman behind me. He was incredibly surprised and grateful. He appeared to be a businessman well mannered, good looking, and not in need of financial assistance. He asked why I did that because he should pay for mine (soldier) and I responded that I practice what I preach as I am a HS teacher who encourages my students to serve others. It was awesome! He told me he would pay it FW at his next city destination! I only regret not getting his name or a picture.