I’ve always taken issue with the idiom “life is no fairy tale,” as in: Life isn’t always a happy story. Not only is this a naive read of fairy tales themselves, it also ignores the fact that the most monstrous acts in these tales are not perpetrated by witches, fairies, or ghosts, but by people both familiar and familial.
That's their power as archetypes. I listened and learned as a kid. I saw what other parents were doing, how they were behaving. Fairy tales led naturally to Shakespeare, and with those two resources, a youth can understand much of human nature.