The phrase "I am happy for you". It is so easy to say and presumably leaves an impression on the listener. May be that is why it is said. But is it really that easy and natural to be happy for others. I think it depends on the type of person that you are and one that you want to become. But when we just acquire the habit of saying it at the drop of a hat, it is more of how we want to be seen. It becomes an exercise at honing our PR skills. It is public posturing at the expense of a sweet concept. It is just a PR exercise where we are unconsciously trying to improve the perception the other person has of us all the time.
Though one may not like to agree with above, but mostly it has been seen that we humans derive pleasure when others are in pain and vice versa. We get a little depressed if others forge ahead of us in the race of life and get elated when the mirror of life returns our image for winners. To some extent, I will call it as "survival instinct" reigning over the Samaritan in us and to some extent you can say-Every one of us has a sadistic shade to his personality. I will say both are true. A little bit of this may be healthy and required for your survival but then the danger is that if you continue being happy with others' miseries, it soon will develop into a habit making you a negative person not capable of seeing the beauties of life and missing the opportunities for his own self improvement. So I will say let al of us be a little bit selfish and think of improving our lot before becoming too obsessed with finding fault with others lest that take away your valuable time and energy.
