Listen to the mustn'ts, child. Listen to the don'ts. Listen to the shouldn'ts, the impossibles, the won'ts. Listen to the never haves, then listen close to me... Anything can happen, child. Anything can be.

This quote means that it is important to pay attention to the things that you are not supposed to do, the things that seem impossible, and the things that you don’t have because they can help give you an idea of what you can do. However, it also emphasizes that anything is possible if you believe in it. No matter how improbable it may seem, anything can happen and you can become anything you want if you put your mind to it.