How do you think the world would be like if when anyone makes a mistake and there wouldn't be any more opportunities for them ? Treating someone well when they are bad is difficult. You have to be a better person to change someone for good.
It turns out that an optimistic attitude helps us be happier, more successful and healthier. Optimism can protect against depression - even for people who are at risk for it. Optimism may even help people live longer.