Few people can successfully sail through life without receiving a single piece of constructive criticism or brutal honesty. Some people can become so driven to be brutally honest, however, that they lose perspective on when such advice is not strictly necessary or helpful. Some brutal honesty delivered by a trusted friend or mentor can be the push a person needs to effect a positive change, but some people enjoy being brutally honest simply for the brutality.
One reason a person may become brutally honest is upbringing. He or she may be the product of a hypercritical set of parents who used harsh criticism as a motivational tool. There may not have been many examples of discretion or tact when it came to expressing opinions of others. A parent or sibling may have looked at a piece of artwork and pointed out all of the flaws instead of praising the child for his or creativity or originality. This negative, critical programming from childhood may survive into adulthood as a brutally honest demeanor.
Some people become brutally honest as a defense mechanism to deflect criticism of their own deficiencies or shortcomings. By putting on a good offense through brutal honesty, they minimize the risk of others judging them equally as harshly. These people often seek out careers as professional critics or judges, strongly believing the only way to help professionals to improve is to be brutally honest. Harsh criticism is seen as a necessary evil, not a lack of tact.
For others, being brutally honest signifies a lack of emotional growth. Many people would love to be brutally honest more often, but a sense of propriety keeps them from overstepping their bounds. Some people who pride themselves on their brutal honesty, however, have a poorly developed social filter when it comes to tact and politeness. They aren't always aware that their critical comments could be personally hurtful or socially embarrassing. They may feel justified by publicly saying what others were thinking privately, but they simply lack the sense of propriety which should prevent such incidents.
Some famous celebrities known for their brutal honesty, such as the acerbic British judge Simon Cowell on American Idol, may do it to prevent future disappointment in an industry rife with even harsher critics. Some may be brutally honest because they believe the recipient won't take criticism seriously unless provoked or shocked. There may even be some people who are brutally honest simply for the sake of watching other people suffer emotional blows from harsh criticism, whether or not the critique has any actual basis in fact.