My Grandfather was in the Navy during WWII. He was on a ship that was attacked by the Japanese and went down. I assumed, because of his age that he was in the war, but didn't find out any specifics until I was in High School. He never talked about it and my mom never told me as she didn't want me to accidentally bring it up around him when I was younger. Even after I found out, he never once talked about it to me.
My oldest Uncle, who was the only one he ever really talked to the War about, said it was just horrific what he saw and it was a miracle my Grandfather made it back.