A negative perception causes us to look at life as a source of sadness, to think of the world as unjust, to view others as malevolent. This way of thinking builds upon itself, becoming harmful, bringing misery to the thinker.
If negative perception is the cause of such misery, then in order to help others, we should try to displace their negative perception with a positive one. We cannot control life and remove the challenges that others face, we can only try to influence the way they interpret their challenges.
So life will happen: illness, injury, disablement, separation, death. But what is not necessary, is disappointment or despair. By altering perceptions, from negative to positive, misery disappears.