The Fake Wellwisher

Often, when you are not too happy, you might find a lot of people empathising with you. And, that is a good thing because you feel you are not alone.
However, when things turn around and you are happy again, most of those people would continue to be happy for you but there would be a few who would suddenly vanish. All your deep ties appear broken.
I wonder why that happens. Maybe it is human nature that brings out the good in people when they see others unhappy and that somehow makes them feel their lives are so much better.
But it is much more difficult for them to see the same people become happy, maybe because it rubs away the special feeling that they have enjoyed till then.
Truth be told, once you identify this behaviour, you should be even happier than before because now you know that someone is jealous.