What i believe the meaning is…… we try to leave marks on the world for people to remember us. John green is saying we leave scars, on ourself, With every mistake we have we harm ourself. Although i haven’t dealt with this in a very long time i understand the pain people who do. Tons of my friends leave scars on them self but marks on me. “They say they aren’t special because the world doesn’t know about them but thats insult to me because i know about them” ( fault in our stars) I wish people could see they don’t need to leave their mark on the world, because they leave it on me. Their kindness, their hope, their sadness. All of it.