Suddenly it feels like our world has lost all light, and is dim and misty. We are wandering alone in the corner of this world. Sometimes we really want someone to walk with us, but we find that the person's destination is different from ours. So that person becomes a passer-by in our lives! That person left, and we walked forward alone again! After walking for a long time, we found that we have not met our heart again. We are decent people, then we comfort ourselves, we don't need friends, friends are just there to relieve loneliness! So we are arrogant and think that we don't need friends. We boldly move forward in the dark world. Because of our arrogance, we become passers-by in other people's lives! After walking for a long time, looking back, we realize that we have missed so much.