As you grow older and get to hold a grasp of how things work

As you grow older and get to hold a grasp of how things work, you will then see what really matters most. You will learn that it is not really necessary to let everyone in your premises just to feel that your existence is validated and just to feel like you belong in a particular crowd. It is okay if you had to cut some toxic relationship with people, or walk out and leave arguments that don't serve you. You should learn not to compromise your peace and happiness over things that matter less and over people who don't even care about how you feel. Your mental health matters a lot—be brave not to look back and just be on your way. Let them hear the sound of your footsteps fading away, let them and let go. 

Letting go is not always a loss.