I had three grandparents who served in WWII. My paternal grandfather served on a destroyer in the Pacific Fleet. I'm not sure exactly what role he played, but it was involved in intraship communications and maintaining the navigation system. In the Pacific Fleet, they liked to move people around and take experienced people off one ship and add them to a new ship to help a green crew shake out, so I imagine Grandpa probably played a number of different roles over the course of the war.
Mom's dad served as a bridge engineer in Europe with the 9th army. He built a few bridges under enemy fire, but spent most of the war building camps and depots for the massive US supply effort, including a series of staging camps called the Cigarette camps for the withdrawal of the US forces from Europe after the war. The logistical war and the engineer war went on long after Germany actually surrendered, and they were some of the last men to come home, often being asked to help rebuild the European infrastructure American bombers had played such a role in destroying.
And Dad's mom served in the Navy as an aircraft mechanic, providing maintenance and repair services for aircraft engines.
Rather proud of the fact that all of my grandparents' service was honorable and successful, without them being required to look a man in the eye and kill them. I'm pretty sure Dad's dad's destroyer saw its share of action, and Mom's dad got shot at, but neither of them fired a shot in anger. Lot of servicemen like that, and their contribution was frequently just as valuable as the front line infantry.
