Light Yagami/Harry Potter
The other two challenging experiences?
The first 24 hours of his consciousness ranked first.
The second was the time Dudley had asked for Light to either be moved to his room or threatened to move into Light's 'room' aka his cupboard under the stairs. Vernon had not been pleased his child wanted to be next to his 'freak' nephew. Petunia had been hysterical. Dudley, all of five years old and lonely from being moved to a new pre-KG, had thrown a tantrum that proved his blood-ties to Vernon. Toys thrown and broken, broken wooden blocks and splinters across the floor, and the only real child in the house breathless from the sobs that had racked his body for an hour straight.
Light had been the one to calm Dudley down. And Petunia had a resigned look on her face as she and Vernon gave in to Dudleys' first serious demand.
It was not the last time they did so either. They gave in rather quick every time after, not wanting their darling son to overextend himself again.