In adolescence you are immortal, will live forever, and you have a passionate sense that nobody in the universe has ever experienced your thoughts and feelings. Parents are old fogeys, old farts, who have no idea what they are talking about, and you and your peers will make the world a new.
This is great until tragedy strikes or frustration and depression sets in. One day you may realize that those things that happen to other people have now happened to you and you have a brush with reality. Innocence is lost, naivete decreases, the harsh aspects of maturity start to appear.
Life is full of pain and sorrow, heartache and betrayal, remorse and regret, stupidity and ignorance, jealousy and possessiveness, meaness and cruelty, sadism and masochism, fear and rage - as the bumper sticker so eloquently and succinctly says - "Shit happens!" My favorite said, "Mega shit happens!" When my two kids were killed, I understood. Reality was in my face.