Situation: A drunk at a frat party sees three coeds and yells, "Hey, any a you girls wanna get laid?"
Nice girl: Winces slightly, but continues to stare straight ahead, pretending not to hear. Thinks to herself, wow, he must be really drunk. My mother was right about these parties.
Average girl: Looks disgusted and mutters to her friends, "What an asshole!" Thinks, I'm never coming to another one of these stupid keggers again.
Sociopath: Calmly replies, "No thanks, I hear you're a lousy lay." Hopes his friends heard her comment. She is gratified when when her friends give her admiring looks. Later, on the way out, she says in a soft voice to the guy, "Seriously, don't you ever wonder why you never get laid?" When she sees the look of discomfiture on his face, she feels good.
Situation: You become a nurse.
Nice woman: Genuinely wants to help people. Is a cheerful, friendly presence; her patients tend to end up assuming that most nurses must be really nice. Actually likes most of her patients, and feels sympathy for many. When the other nurses make jokes about various patients, she remains silent, a little dismayed at their insensitivity.
Average woman: Is drawn to the job because of the pay, benefits, and job security. Hates cleaning bedpans, avoids it when possible. Treats her patients professionally; feigns sympathy when that is called for, and actually feels it on occasion. Whenever a good-looking male patient arrives on the ward, tries to be assigned to his room.
Sociopath: Works on a cancer ward because she gets a certain frisson from being around dying people. Gives patients and their families alike her bromides about the Great Beyond, knowing that she will make an impression because they are at an emotionally vulnerable moment. Gets sort of high thinking about what a good person she is as she does this. On the few occasions she gets a very rich patient, she acts extra nice, hoping to be remembered in the will. Whenever she dislikes a patient, she surreptitiously decreases the amount of painkiller in his IV.
Situation: A potential rival for your boyfriend's affections appears on the scene:
Nice woman: Fervently hopes that this woman doesn't steal her beau. Acts more clingy than usual around him.
Average woman: Accuses her boyfriend of being attracted to the woman, then makes catty comments about her weight and clothing.
Sociopath: Tells her (white) boyfriend that the woman's last boyfriend was a 6' 8" black guy. Tells people in their circle that the woman has been saying nasty things about them. Tells the woman to stay away from her boyfriend. Keys her car.