According to psychologist Dr. Joshua David Stone, people criticize others out of fear and jealousy. Individuals who are critical of others tend to have low-self esteem and a lack of love for themselves. Individuals who constantly criticize others tend to lack control in their own lives and project their own self-doubts onto others.
Criticism comes in many forms. In dysfunctional families, it is common for parents to criticize their children by telling them they are not good enough or they are worthless. This type of criticism often stems a parent's own self-doubts or perceived lack of success in his own life. When a highly critical person visibly hurts another with their comments, a common reaction is to state that the individual is "oversensitive."
Individuals with low self-esteem and control issues often use criticism as a defense mechanism. For example, individuals who are raised in abusive homes, where criticism is considered the norm, tend to believe that they are a target for criticism in every day life, which leads them to criticize others in order to protect themselves.
Constructive criticism is a form of criticism that is meant to improve a situation and is a common practice in educational and workplace environments. In the workplace, constructive criticism is typically presented as a set of ideas with the sole aim of improving products or services.