When my grandmother told me the story of leaving Germany in German for the first time. What had been presented to me as a perfunctory list of facts before now had color and smells and emotion and pain and loss. I heard the side of the story that was a Jewish teenage girl, going through normal teenage things, all while the most incomprehensibly worst thing ever thundered around her. It let me see a lot of who she was deep down and made me feel closer to her. There was also a lot of humor, which is a testament to who she was.
Second most rewarding moment was when I came home from studying abroad in Austria, and I said something to her, and she said, "Oh dear God, after all I've been through, now my grandson he's a Viennese." That woman spoke 5 languages and had impeccable comedic timing in each one.