We took our four-year-old niece to Disneyland during their Halloween events. She was very, VERY excited to meet Jack and Sally. The line to meet them was predictably long, and of course there is always concern about monopolizing a character's time. When it came to our turn, Niece was chattering away about how much she liked them and how she visited their 'house' (Haunted Mansion Holiday).
Conscious of time, I tried to get her to pose for a photo. Jack looked at me and said, "No, it's okay. Let her talk." He and Sally spent a long time kneeling at my niece's level talking to her, then posed for several photos with her and our whole group. They made her feel like the only person in the park, and she was bubbling the whole rest of the day. It was wonderful! They really made our visit magical.