Internal childlike joy is natural.  Narcisissists forgot this joy and bliss for no
apparent reason so they are envious of anyone who has it. They want it
back but don't know how to get it so often times they will display
intense jealousy and become mean, evil, critical, condescending,
threatening to the joyous person in an attempt to invoke misery 
in the joyful one, erroneously thinking they can steal the joy 
of the other person. 

You can't steal something that is inside of all of us and
freely available. 

It costs no money. It is a state of being.

It can't be bought or sold. 

It's in a smile. A warm and good feeling. A happy memory.
It is appreciation. Noticing the energy of connectedness of all.