Magic is dangerous because it makes unworthy practitioners lazy and makes them take a lot of good things for granted.

Young men, especially, have this attitude of "I am a prince. Train me. I deserve to inherit everything you have." Such people never hear from me again.

There are no "chosen ones" in magic, because magic is a lot of hard work and self-discipline that even entails abstinence from grounding activities such as sex. That is why many wannabes end up as complete failures.