Death, pain suffering.
All parts of life, all living beings experience the pain of life and the absence of life. The pains of losing someone close, someone who meant something to you. It hurts it makes like unlivable, unbearable. The pain of love is nothing short of destructive. It's not worth it but having someone love and care about you is addicting, intoxicating even. Hearts are broken day in and day out. Everyday someone experiences the pang of loneliness. And yet the world just keeps rolling on leaving those people to rot alone in their despair. Left to die alone or grow angry at the world.