What is Willow's problem with yellow crayons in Buffy the vampire slayer?

Answer 1

In season six, Willow turns evil due to Tara's death. With the ability to feel everyone's suffering, she decides to end the world with her powerful magic. In the episode 'Grave' at the sight of the place where she will perform her apocalyptic ritual, Xander appears and tries to get her to come off the issue by reminding her of how long they'd been together. He reminds her that in preschool she got upset because she broke the yellow crayon and wouldn't tell anyone to show her how much she's changed, and she breaks down and turns back into her own self.