In popular usage, eccentricity refers to unusual or odd behavior on the part of an individual. This behavior would typically be perceived as unusual or unnecessary, without being demonstrably maladaptive. Eccentricity is contrasted with "normal" behavior, the nearly universal means by which individuals in society solve given problems and pursue certain priorities in everyday life. People who consistently display benignly eccentric behavior are labelled as "eccentrics."

Depictions of eccentricity

Eccentricity is often associated with genius, giftedness, or creativity. The individual's eccentric behavior is perceived to be the outward expression of his or her unique intelligence or creative impulse. In this vein, the eccentric's habits are incomprehensible not because they are illogical or the result of madness, but because they stem from a mind so original that it cannot be conformed to societal norms. Edith Sitwell wrote:

"Eccentricity is not, as some would believe, a form of madness. It is often a kind of innocent pride, and the man of genius and the aristocrat are frequently regarded as eccentrics because genius and aristocrat are entirely unafraid of and uninfluenced by the opinions and vagaries of the crowd."

Characteristics:

Nonconforming attitude Creative
Intense curiosity Idealistic
Happy obsession with a hobby or hobbies
Known very early in his or her childhood they were different from others
Highly intelligent
Opinionated and outspoken
Noncompetitive
Unusual living or eating habits
Not interested in the opinions or company of others
Mischievous sense of humor
Single
Usually the eldest or an only child

Comparison to the norm

A person who is simply in a "fish out of water" situation is not, by the strictest definition, an eccentric since, presumably, he or she may be ordinary by the conventions of his or her native environment. Eccentrics may or may not comprehend the standards for normal behavior in their culture. They are simply unconcerned by society's disapproval of their habits or beliefs and most often display extreme individualism. Many of history's most brilliant minds have displayed many unusual behaviors and habits.

Some eccentrics are pejoratively considered "cranks", rather than geniuses. Eccentric behavior is often considered whimsical or quirky, although it can also be strange and disturbing. Many individuals previously considered to be merely eccentric, such as aviation magnate Howard Hughes, have recently been retrospectively-diagnosed as actually suffering from mental illness (obsessive compulsive disorder in Hughes' case).

Probably the best example was Serbian-American physicist and inventor Nikola Tesla. Another famous eccentric was renowned theoretical physicist Albert Einstein; his eccentricities included picking up discarded cigarette butts off the street in order to circumvent his doctor's ban on buying tobacco for his pipe, piloting his sailboat on windless days ("for the challenge"), and lecturing his 8-year-old nephew on physics (including a 2-hour exposition on the Newtonian properties of soap bubbles).

Other people may have eccentric taste in clothes, or have eccentric hobbies or collections which they pursue with great vigor. They may have a pedantic and precise manner of speaking, intermingled with inventive wordplay. Behavioral eccentricities have often been classically associated with psychological profiles indicating overcompensation, insecurities, unresolved childhood issues, involuntary celibacy and other sexual issues, unrequited love, heartbreak, and other romantic issues, repressed feelings, social ineptness, monomania, or a variety of other influences, even if the person would not necessarily be classified as insane. Some accepted psychological profiles that are commonly attributed to eccentrics are the Oedipus complex (a primal desire on the part of a young male to compete with his father for his mother's love and affection), Napoleon complex (colloquial term used to describe a type of inferiority complex suffered by people who are short), Peter Pan Syndrome, obsessive-compulsive disorders, and autism spectrum disorders, most notably Asperger syndrome. Eccentric behavior has also been attributed to drug use.

Many individuals may even manifest eccentricities consciously and deliberately, in an attempt to differentiate themselves from societal norms or enhance a sense of inimitable identity; given the overwhelmingly positive stereotypes (at least in pop culture and especially with fictional characters) often associated with eccentricity, detailed above, certain individuals seek to be associated with this sort of character type. However, this is not always successful and the individual in question may simply be dismissed by others as just seeking attention. Extravagance is a kind of eccentricity, related to abundance and wastefulness; refer to description in hyperbole.

Psychologist Dr. David Weeks mentions people with a mental illness "suffer" from their behavior while healthy eccentrics are quite happy. He even states eccentrics are less prone to mental illness than everyone else. This may be related in the same way that introverts (introversion) suffer more from their mental illness than do extroverts (extroversion), who tend to make those around them suffer instead by their actions or deeds (outward expression of their illness rather than inward). According to studies, there are fifteen distinctive characteristics that differentiate a healthy eccentric person from a regular person or someone who has a mental illness (although some may not always apply). The first five are in most people regarded as eccentric: