If you're graduating from college or high school this month, maybe someone will give you Charles Sykes's 50 Rules Kids Won't Learn in Schools (St. Martin's Press, 2008). It's not bad, starting with its short and appropriately sour rule #1: "Life is not fair. Get used to it."
Many of the rules emphasize the need to work hard in a competitive environment: "The real world won't care as much as your school does about your self-esteem.... No matter what your daddy says, you are not a princess....Life is more like dodgeball than your gym teacher thinks.... Flipping burgers is not beneath your dignity. Your grandparents had a different word for burger flipping. They called it opportunity."
Other rules advise patience: "You are not the first and you are not the only one who has gone through what you are going through.... Grown-ups forget how scary it is to be your age. Just remember: this too will pass." Sykes asserts the importance of both objective reality ("Pi does not care what you think") and personal relationships ("Don't forget to say thank you").
Two rules in particular, if followed, would forestall lots of sadness: "Your sexual organs were not meant to engage in higher-order thinking or decision making," and "You are not immortal."