1. No, love is not like the ones in movies even when you're an adult. Even if you find a great partner, you'll be too busy with work and tired to spend as much time with them as you thought you could.
2. Remember you were the most popular girl/guy in school? Welcome to the world where that doesn't matter a bit.
3. Remember the kids you bullied because you thought they were too nice or were nerdy? They are now all successful and loved by many. Now you're the oddball.
4. You have to work harder than you did in school. You think final exams were stressful? Try finishing a job before the deadline so you won't get fired and still be able to pay your rent and food.
5. That great guy/girl you left because you weren't done "fooling around". You missed a very good relationship opportunity there and will regret it for a long time.
6. Yes, you have to make a career choice. Yes, it's not always easy.
7. You will pay for your rent, your bills, your travels, your clothes, your haircut, lots of taxes. Pay pay pay. Yep, it will never end.
8. You're an adult now. Your parents can't come to your rescue if you screw up at job or in your relationships. You have full-responsibility of your life and decisions.
9. You will have to accept some of your childhood dreams won't happen. Don't make it the end of the world, find new things.
10. You know how you and your best friends were seeing each other every day or at least every week? That will change. Nobody has enough time or energy to see you and other people anymore. You won't have enough energy or time too.