why generally people wants to see other unhappy

Because then you feel that you are not alone. I think it's normal for this to happen because usually a person will feel all the bad things are happening to them, but then they realise that there are other people who are just as sad. It makes me more comfortable to see someone in a bad situation lol but I know most people are probably like that anyway :P

percentage of this type of people are very high ,they can grow ,they enjoy negative things ,ignore them

They are like that because first of all, they are the saddest people on the planet. These people wants other people to join in their bandwagon of losers, or the sadmen's club. They don't want people to be happy because deep inside them, they desired to be happy but circumstances and character won't allow them to. second, they are the most insecure. When other people are striving and flourishing, these things magnifies the insecurity of the insecure. third, They are mediocre. Mediocre people hates the successful people, because they want to be successful but they won't let go of mediocrity. So when someone falls or sad, or failed. They will be elated. It brings them great joy for people to be on their level. Lastly, they are just mean and cruel, something of a loophole in their character. Good day

world is like of that ,we have to live with these kind of persons ,still we have not to loose positive things

It is plain jealousy that drives them to act that way. If you are happy and successful, other people especially from your own circle will tend to hate you. Because their life is a failure and miserable. They are losers and they would want you to swim in their miseries too. If you are getting ahead over the others, they tend to hate you and destroy you because they cannot accept the fact that you are succeeding and happy while they are not. In my country we call it "crab mentality". If you put crabs together in an open basket, you can just leave it and can be assured that not a single crab can escape from the basket. Because if one crab dares to etch his way several ninch up the basket, the other crabs below him will grab him and pull him down.

It is so sad to know that there are really people who take pleasure in seeing other people in pain. But one thing I know about is, that those people who seem to make fun of others' unhappiness, are really the most unhappy ones. Coz they are trying to cover up what they truly feel and would not admit themselves that they are in a lot of pain, too.

I have know many people like this and I will never understand. Its like they are jealous of other people happiness. I'm always happy for others good luck. I can't imagine living a life being happy at other peoples bad luck. I can't be friends with people like this so I stay away from them once I see that is how they are.