Minor spoiler: in the bluest eye a young black girl obsesses over a white female doll with blue eyes. Before I read it, I never considered the impact that the idealization of white beauty could have on minorities. After reading that book, I realized how important it was for children to be able to look up to role models (fictional or otherwise) that look like them.
In my own life, I have had my own share of fantasy role models (I am a huge Tolkien fan, and when I was younger I loved all things fantasy) that shaped my own identity, and after reading The Bluest Eye I had to consider the idea: how would those books have affected me if all characters looked nothing like me? I do not think the effect would have been positive.