How we change what others think, feel, believe and do
Jealousy occurs when we fear or experience a loss to others. Thus the famous jealous lover who sees all other people of the same sex as potential rivals who will steal away the mate.
Jealousy is slightly different from envy as it involves a third party and is about loss. Envy is always about potential gain.
Envy and jealousy overlap in the scenario where another person is admired by everyone else for possessing something. This gives you a 'double whammie' as it means they are both giving someone else attention and also not giving you attention. You are envious of the attention that they are getting and jealous because you see them 'stealing' that attention from you.
What is happening here goes something like this:
Notice how we work hard to justify to ourselves that feeling jealous, an emotion we may consider to be generally undesirable, is in fact ok for us to feel in these 'special' cases.
Sometimes we even retrospectively create this emotion when something bad happens to other people, so we can say 'they deserved it'. Again, this is all about justifying to ourselves that we can feel bad about other people.
Beware of making others jealous of you: the results can be hazardous. You can, however, make people jealous of someone you wish to socially ostracize.
Lazarus, R. and Lazarus, B. (1994), Passion and Reason, Oxford University Press, New York