hi sheetal , that was an interesting subject. To be frank, being happy naturally is an art of living. That can be taken as a practice in our day to day life to think positive and live positive.Your face expresses all your inner feelings whether it is good or bad , sad or happiness. I think such people are not born but brought up and must have learnt from their valuable education and lessons from their life. We all should be like that. Everyone likes to see a smiling face and friendly approach from us. I think we can bring that kind of looks on our face also with a regular practice . Chaand had asked how to bring such smiles our faces. Just try it by standing before a mirror with a beautiful smiles on your face and a happy face . And also try out a sad and a frowning face before a mirror. So this way you start avoiding a bad face by yourself and try to keep a smiling face always. try this method. good luck.