could giving up on life of a active and alive being be a good things?

How bad is it to put someone out of pain by killing them? How would culture and religion be a component for consideration. When was euthanasia discovered. What are some devices to create a painless way to go? is giving up on life unreasonable? what about rare cases when people can recover from a death like state? is it really up to you when you die or does an unknown force control that?