My three-year-old son is currently going through a phase in which he fixates on something he wants. He won’t give up until he gets it. In driven, ambitious adults this would be admired. In a three-year-old, however, it’s typically accompanied by a tantrum. He wants the toy his brother is using, the extra cookie, or to go to Nana and Bapa’s house so badly. And in his mind there’s no reason that shouldn’t happen... immediately.