You discover that a college diploma doesn't mean squat.
Fact: More than 40% of college students graduate owing over $20,000 in student loans.
You're thrust into college at an age where you barely know your ass from your elbow, let alone what you want to do with your life. So you end up paying out the wazoo to study something dumb, like philosophy or religious studies, because it sounds cool. Four years later: Congrats! You have a nice piece of paper, no professional skills and thousands of dollars in debt.