Rejections hurts. Always. For high school seniors, most of whom have never had their lives and accomplishments subjected to such scrutiny, being turned down by a college (or colleges) can be downright devastating. Why wasn't I good enough? What should I have done differently? Why don't they want me?
Sadly, these are questions that often can't be answered. And for the student whose college plans have been thrown into chaos and uncertainty by the receipt of a big fat "NO", it's not even worth it to consider the whys. Focus instead of moving forward and making the most of the opportunities you've got.