I've only seen the fire truck ritual twice (once from inside the plane and once from a neighboring plane).

I don't remember exactly when it was that the captain of the flight I was on retired, but I do remember shaking his hand on the way off the plane and thanking him. It was a surprisingly emotional thing for me, but I guess it kinda makes sense because I realized that he had delivered countless passengers like me safely to our destinations over the course of his career.