Truly nice guys are about as small a percentage of the population as sociopaths: roughly 3%. The vast majority of us fall into the middle -- or "average" -- category. But the following vignettes should give a sense of the kinds of behavior exhibited by each.
Situation: A young man inherits a lot of money. How does it influence him?
Nice guy: Feels guilty about the inheritance ("Why me?") and devotes his life to helping others. Tries to hide the fact that he's rich.
Average guy: Joins a corporation to prove that he could have made it on his own anyway. At 40, mired in middle management, he realizes his would have to start his own company to make his mark, and decides to devote himself to enjoying life instead. Has the vague feeling that his money makes him better.
Sociopath: Flaunts his wealth, and feels no qualms about using his money to get women. Hires a lot of servants, but assumes even the honest ones are constantly trying to rip him off and not working as hard as they should be. Devotes himself to making their lives miserable. Never doubts for a moment that his inheritance is his God-given right, and that it makes him a superior human being in every way.
Situation: Someone is given a puppy by a friend.
Nice guy: Falls in love with the puppy at first sight, and cares for it with the kind of concern most people reserve for their children. Takes it for a walk daily, lets it sleep in his bed.
Average guy: If he keeps it, he treats it responsibly, missing only a couple of checkups with the vet. After a while, realizes it helps him pick up girls, and values its usefulness as a prop. Feels moderately affectionately towards it, and appreciates its loyalty. Feels sad when it eventually dies, but wonders if he shouldn't feel sadder.
Sociopath: Forgets to feed it half the time, but never forgets to torment it in many ways big and small. When it goes to the bathroom on his floor for the third time, kicks it in a fit of rage and kills it by accident. Although he won't admit it to himself, it feels strangely good to do so. Doesn't want to get into trouble, though, so buries it in a forest that night. Tells the person who gave him the puppy that the coyotes got him, and that he is absolutely heartsick about it.
Situation: Someone is a high school track coach.
Nice guy: Praises his athletes, tries to make them feel good about themselves, always keeps in mind that he is trying to mold young people, help them with their lives.
Average guy: Bears in mind that he is in a position of responsibility, but the win-loss record definitely comes first. Makes an honest effort to be encouraging to everyone, but somehow ends up paying more attention to his better athletes. May try to be a friend rather than adult authority figure to his athletes.
Sociopath: Takes all the credit and none of the blame for his team's record. Tries to get more out of his male athletes by equating their masculinity with a better performance for him. Demeans those who don't perform well, and does so in front of their teammates. May sexually exploit his female runners.
Situation: Someone is 6' 6" and 245 pounds of solid muscle.
Nice guy: Feels self-conscious because of his freakishness; gets embarrassed whenever anybody refers to his incredible strength.
Average guy: Shows off on a regular basis, and glows whenever anyone expresses envy of his physical attributes.
Sociopath: Emphasizes his instinctively menacing manner by always standing quite close to whomever he is speaking to, so that the other person has to look straight up at him. Whenever he wants to get his way, he accompanies his suggestion with a slight lunging motion towards the other person so as to underline the implicit physical threat he represents. Is not hesitant to use his fists.