In WWII, my dad was a "merchant marine", he served as a cook on a supply ship. It was not until I was out of high school that I realized that Dad WAS in the war (I always thought he "had it easy" on a ship).
See, Dad did not speak of the war much, other than in a joking way.

THen one day he explained about how they were a target, because they carried food, fuel and ammo to those serving in the European theater of operations. He spoke of how one of the ships in his convoy, on one of the runs, exploded (either from an accident on the ship or mine in the water) and how the ship went down with all hands.

I saw Dad's service differently after that. Dad died a few years later at age 83.