Why people jealous of experts for thier quality or pity their lack of quality ?

It is the way human behaves and it is human nature

Its always natural for a less knowledged person to be jealous of a person blessed with Knowledge

May be they jealous because they don't able to do the same.

Jealousy is a natural attribute.  This instigates the jealous person to improve. If fairness and strict compliance with rules is adhered, jealousy may be a positive factor. But when you adopt unfair means out of jealousy, this will be counterproductive.

The experts are experts because they possess specialized knowledge. If the non expert is also doing the same thing in an inferior way, he will lag behind and be jealous of the expert. The right way is to acquire expertise and not be idly or unfairly jealous.

jealousy comes when we hate a person's site. if our friends or relative hurt us by a word or some thing. we start disliking them and after then if they achieve any thing or get promotion we get jealous.
for example you and ur friend studies in the same class. if you love him and take him like ur own you will you dont not feel bad if he gets higher marks.and if any stranger gets higher marks you dont bother.only if your friend teases you for his marks or others compare you with him then the jealously arries.this is according to me.hating a person bring jealousy

They don't know what they want.

human nature

Many people who are not brilliant are jealous of others because they have what they dont...it is a natural human tendency to be jealous of someone who is better than you ..as long as it is within limits it may even spur you to better yourself !

It is a human nature so it is quite normal. But this is a disease.

Jeolous is by nature but every time it is not good it become bad.

Jealousy, is a natural human emotion, negative emotion though, which is obvious when someone proves to be more smarter than you are.

Its the nature of any human being. But one can control it...

This is normal. Actually they also want to be expert but may not be able to due to several reasons and the only thing they could do is to get jealous of people having the quality in which they are lacking.