Answer:
we should be happy because by seeing current situation this world is full with jealousy , hatred and many things , and people doesn't have time for interacting with each other if we be sad and think negative we would lose the hope to survive in this world and by being happy we would have a hope to live and have a feeling to continue this life and experience all the beautiful things which are waiting for us to experience so by living happily will bring a hope to continue our life
( hope it helps )