It follows that old saying, "you always hurt the ones you love". Teens are just beginning to mature emotionally. They are dealing with issues that mom and dad used to solve for them or help protect them from. It is frustrating to have to decide what is right and wrong on your own. When they chose the wrong, they react with anger 1) because they feel badly 2) they feel like they are being put under the microscope. They haven't yet realized that it's ok to be angry but the attitude must adjust to work positively with the issue. That's just one point and I could be looking at it differently from what you asked. Great question.