You should learn to be happier than before, and smile even if you are sad. Learn to be cold-blooded, only for those who are good to me. Learn to be lonely, no one will protect you as a treasure. Learn to be cruel, kill it, and let it go. Learn to be rude, get out of here and stay. If you work harder than others, you will have one more grade; If you are more ambitious than others, you will be more promising.