Jealousy is a natural provocative emotion, but when it gets out of hand, it defeats its purpose and can alienate a spouse's affection without real justification. Jealousy implies fear - fear of losing the affection and fidelity of the other person. Jealousy may be necessary/justifiable (based on observation) or unnecessary/unjustifiable (not based on fact but on insecurity/suspicion). Jealousy is self-defeating as love and fidelity cannot be forced through suspicion and surveillance, the other person resents the lack of trust, and it is often a symptom of immaturity. Jealousy is expressed through criticism, suspicion, questioning, nagging, demands for explanation, moodiness, loss of respect, attempted domination, and restriction of freedom.