The Reason of Keeping a Person Alive

I can never understand how keeping a person alive matters so much to everybody, when they failed to let that person be happy. I can also never understand why married couple want to have children when they successfully failed to carry out their duties in protecting their children, who are dangerously vulnerable especially when they're young, and to nurture them with care, affection, and the principles of life. In the end, without even being cynical, the answer is pretty obvious; everybody doesn't want to be left alone, especially in the state of sadness. Everyone takes things for granted, and few could comprehend the idea of being isolated, yet everybody don't want to be alone, because they ARE afraid of being alone. It's especially hard for me to congratulate someone for having to become parents to their newborn child, and I find it unforgivable when they ever isolate their kids wherever they go.