Returning to the Senior Year of High School: This Time I Don't Want to Be a Waste Again

Do you have any regrets in your life? Do you regret that you failed to cherish your youth and get admitted to a good university, so that you have done nothing in your life? Or do you regret getting married too early or choosing the wrong person/missing out on your first love? Or does it make you regretful that your son is no longer around when you want to raise him? If you could go back to your senior year in high school, how would you make up for your regrets?