Rejection
It only prepares you for what you are really looking for, for the one you don't want to reject and the one that doesn't want to reject you. On either side of the fence, rejection is nothing more then a preparation for what can be if you allow it. Allowing it is different subject completely, but when you are ready to stop rejecting or when you find someone who wants you just as you are... then you have found something worth exploring. Until then, it is all practice.