Many times, you don't know how much you have missed, so when the truth of the matter begins to become clear, you suddenly realize that you have missed many of the most important things, so you have lost what you need most. After suddenly awakening, all that is left are memories and sighs hidden in the years.
Too many people have been missed, and sadness will find them, so take a closer look at the people around you. Maybe she or he you don't care about has spent his or her life trying to get close to you, and then ends up regretting it because of you.