What is secret to remain happy?

Two days ago I was with friends in Delhi, at the end of the day we decided to go Lal Quila . As we didn’t have much time and got tired, we decided to sitting beside a wall on a so called bench outside Lal Quila. So many people were also sat on that long bench. Some were sitting idle, some were talking and some were giving fake smile towards their friends who holds camera. I was also giving fake smile and when I got tired to smile, I began to watch people around me. I could watch people going here and there, looking like they are searching for some happy moments. I was watching towards right, suddenly a 7-8 years old girl came from left to right direction. She wore dirty frock. She was walking in different way, like there are little springs in her legs. She had her own little world where she was walking. In the crowd of people, she was looking like little lotus in that mud of people. While I was observing her, suddenly I thought “What she is doing here alone? Is she is a beggar, who forgot his job. Then I saw towards left to ensure this. But I saw a woman is also coming towards her, might be she is her mother. That woman sat on same long wall which was used as bench. She called that girl and that girl ran and sat beside her. I never saw a child sitting quietly for few minutes especially when somebody tell him/her to do so. That girl also did same and began to jump on little springs of her legs in circular path. Suddenly she sat near me and gave me mysterious smile. Then she again starts her jump game. While she was playing with herself, her mother was looking like tired traveler of journey of life. She was in deep thought and she may be thinking about problems of their life. She was not looking happy while his little angel has nothing to do with what is going on mind of his mother.

Both that girl and his mother were in same situation and living in same physical and psychological environment. Girl was happy but her mother wasn't  What is the secret of happiness of little girl? When I first thought about this. My mind immediately rose point that because girl didn't know about the problems of life under the shelter and care of her mother. But my eyes told to me that I had seen so many happy children with empty stomach, torn and dirty cloth, mostly barefoot. My mind becomes Manmohan Singh.

During the drought of thoughts in my mind, I realized that children know secret of happiness. Children can be happy in any situation because they have ability to forgiveness. They can easily forget something. They can easily forget quarrel with known or unknown friend, they easily forgive the people and situations who hurt them. I can say that a good memory is one of the obstacles to remain happy. But still I can’t find the all the reason of happiness of that girl.

Can you find?