Even when it did involve a lot of pain , I realize that in exchange for that , there 's something to gain . Sometimes , things may seem so unfair and like the world is against you , but in the end , do n't we become a better person and learn to deal with the harsh reality ? Happiness is fleeting , but in order to appreciate the happiness we gain , we must be able to endure its opposite .

Question: What may be the reason for their statement ?
Answer: They want to cure others ' depression .They want to cure their depression .They want others to feel happier .None of the above choices .