Glenn Howerton has said in interviews that he believes that Dennis is not actually a complete sociopath; and, deep down, Dennis is actually very fragile and has very strong emotions and is in fact the most sensitive and insecure member of the Gang.
However, the only way he knows how to show it is by getting really angry.
This fear of rejection and abandonment also manifests prominently in "The Gang Broke Dee" and "The Gang Group Dates." Dennis's idea for getting his sister out of her depression is to find her a man with no self-esteem, like her, and by putting them together he will be able to continue controlling Dee and preventing her from ever leaving him.
In high school and college, Dennis believed that he was a legend that others looked up to.He later found out that he was wrong on both counts .He believes he has a comprehensive understanding of the mechanics of gay relationships.He knows what it means to be a bear or a twink and understands how a "top" differs from a "bottom"; he explains to The Gang that "speed is the name of the game" when defining the role of a "power bottom" .He often claims to be a God and believes he should be the leader in all cases of decision making.
Dennis's romantic relationships are shallow, and his closest friendships are both codependent and homoerotic (though he believes them to be incredibly cool and masculine).
Regularly, his relationships with his best friends, Mac and Charlie, are portrayed as homoerotic.
The ambiguous nature of Dennis's sexuality has been explored in other episodes and is usually connected to his vanity and need for peer approval. Klinsky was far older (probably at least 40-50 years old), and is described as looking like Rick Moranis.
Much of Dennis's inflated self-image is fueled by others, whether through their attention and admiration or through providing him with schadenfreude at their own misfortune.
Any critique of his looks, however mild or trivial, deeply distresses Dennis and often leads him to extreme behavior.
Dennis is frequently hinted to be a sociopath incapable of feelings but later seasons have taken a more sympathetic approach.