Jealousy is a normal emotion experienced when two people share a social or personal relationship and conflicting feelings of anxiety, envy, insecurity and frustration arise. Jealousy can be normal in some situations, such as professional environments where workers are spurred to strive for better positions or circumstances. However, in other instances, jealousy can be delusional and dangerous, particularly in romantic relationships. Both normal and delusional jealousies may be sub-categorized as they are felt in a variety of relationships.

Family members commonly compare themselves to one another. One common form of family jealousy is sibling rivalry, which affects siblings of all ages. Siblings may compare their accomplishments with one another, vie for the majority of their parents’ affection, and compete to play with the same toy. Sibling rivalry can be felt in an instance where one sibling is more successful than the other in school or career, but it may also be felt if one sibling has a disability that requires extra attention from other family members.

Work jealousy arises between colleagues vying for the same type of position. If one colleague feels that another received, but was undeserving of, a salary hike or a title promotion, he may experience jealousy. He may feel especially jealous if he felt that he worked more diligently to earn accolades that were only awarded to the other person.

Romantic jealousy is common because strong emotional bonds leave partners open to potential extreme heartbreak. According to Psychology Today, when two people join into a romantic relationship with reciprocal love, most fears, vulnerabilities, and insecurities stemming from childhood seem to melt away. However, when a perceived threat—such as suspected infidelity—arises, the insecurities return with a vengeance. Even the sight of an outlying attractive person may cause a normally secure partner to be concerned that the other will “upgrade” to a better model.

Jealousy arises in friendships due to the same insecurities found in other relationships: feelings of comparison, a fear of being replaced, and feelings of competition. Two female friends may discover that they are attracted to the same man and claim that neither will “go” for him. However, they may both begin to feel all three jealous insecurities simultaneously: they may feel competitive to earn the man’s attention, insecure about their individual abilities to win him over, and fearful that the man will ultimately act as a friend replacement.