Great question — answering as the UphillTech team:
Probably nothing special, he says that a lot in the anime, and he says because he finds interesting to observe what humans do in given situations, that's why he sent the death note to the Earth (also because he was bored).
Full answer by blueheart: https://movies.stackexchange.com/a/94341 (CC BY-SA 4.0).
Need it done for your business? UphillTech.
