Dear Nico,
I am very happy to have you as my friend. Am writing this to let you know that education is very important and you need to take it serious. Have you heard anything about opportunity cost?. If no, then let me explain a little bit about opportunity cost to you. Opportunity cost is the best choice that you give up in order to do something else. The opportunity cost of not doing good in class and getting bad grades is to come to the summer school instead of staying at home doing nothing. This kind of attitude will not help you to graduate from high school, your grades will remain ''D'' if you keep on with this kind of attitude your teacher's may not like you. If you keep on with this kind of attitude you may not go to collage. The opportunity cost you have now is to decide to stop playing around and stay with your book. A person with this kind of behavior may not have job, you will be jobless. Now the opportunity cost is that you can live the bad behavior and decide to do the right thing.