People come into our lives for a reason. Sometimes it is for their sake and sometimes for ours. Each is an opportunity to make ourselves better.
Those who are good, are there for support. They encourage the discouraged and comfort the discomforted. The world is a brighter place for their presence.
The evil pose as challenges to be overcome. We learn what not to do and how not to be. Because they darken things, we must shine a light.
Most people are a combination of the two. Though they care, they will afflict you with their problems. Be a good example, by keeping your own house in order.
The world cannot be saved, but it should never be wasted. There are those whose very existence is not for their sake. They fade away once their purpose has been served.
You do not need to like someone to learn from them. Even the worst examples can teach the most valuable lessons. It is from unexpected encounters, that we come to know our world.