Perhaps there are a number of difficulties in life and there are also hundreds of ways to solve and overcome them. However, among all the soluations, complaint is definitely not one.
Life isn't easy, often full of challenges, which require us to face them with bravery and to solve them with wisdom. But that's the meaning of life lies in. We gain the sense of achievement and the joy of growth after the setbacks in our way being solved. Heaven is full of happiness, but it only exists in fantasy. Life is like a mirror, which reflects how we treat it and how we look at it. If we make more effort and less complaint, life will be happier. We should be optimistic, especially when the sorroundings is disappointing and tough, otherwise, we would lose the last stepping-stone which we could stand on to fight against the unexpected and unwanted difficulties.
We have seen numerous people complain a lot about the dissatisfying factors in life, but those who do so never see the disadvantageous situation get better, but even worse, eventually stuck in a vicious circle their whole lives. We have also witnessed quite a few people who complain little but make constant effort, gradually can enjoy a happy life. Thus, we have no reason not to make more effort and less complaint in life to gain happiness.