In 1968 two young sister missionaries knocked on our door, one from America, the other from Belgium. My husband invited them in to show them how wrong they were. He gave them a hard time. At one point in the discussion, he was being so difficult that one of the sisters wanted to give up and go back home. She didn't, and we were later baptized.
Last November those two sisters, now living near Provo, utah, wanted to invite us to their homes for dinner after my husband was called to be second counselor in our stake presidency. I'm glad they didn't give up when the situation seemed impossible.