Forget what your teachers/parents/authority figures might tell you. Magic is good for you. It's kept me healthy and whether you know it or not, it's probably doing the same for you.
I have not been playing very much Magic lately. This fact may or may not be correlated to the increase in minor panic attacks I have been having. Both of these facts are definitely causally linked to the fact that I recently moved out of New York City and haven't had (1) as much free time and (2) a place to play. (Social anxiety can make it hard to try new places/meet new people, it turns out.)