The Paddy's Pub gang from It's Always Sunny in Philadelphia is not a group of people you'd want to hang around in real life. each one of these characters has shown that they are completely selfish -- and that's on their good days. At worst, they're dangerous, none more so than Dennis Reynolds.
Dennis started the show as one of the more level-headed members of Paddy's Pub but his mental state has gradually deteriorated over the course of the show. His womanizing ways have been discovered to be largely manipulative and he holds an opinion of himself that is unhealthy, to say the least. At this point, there is no hiding that Dennis is a full-blown sociopath and there are plenty of quotes from Dennis himself that can back this up.
"Have you ever been in a storm, Wally?"
The Paddy's Pub gang really don't belong in any civilized setting, least of all the quaint and quiet life of suburbia. So when Dennis and Mac decide they want to move out of the city and find a nice neighborhood to settle down in, you knew it was only a matter of time before that dream came crashing down.
The more slow-paced life of the suburbs immediately annoys Dennis, most of all when their friendly neighbor Wally who continues to try to connect with Dennis by discussing the weather. Finally, Dennis snaps threatening poor Wally with a "storm of fists".
"I have to have my tools!"
It's hard to differentiate between the weird sexual activities Dennis is involved in and the hints that he leads a much darker life. While there hasn't been any solid evidence that he's ever killed someone, there sure is a lot to make us suspicious. Not least damning is his "tool kit".
After feeling he was wronged at a high school reunion, Dennis retreats to his car where he searches for his tools in his truck's hidden compartment. Seeing as those tools include zip-ties and a camcorder, it raises a lot of red flags.
"I am a golden god!"
Confidence can be a great asset for a person to have. Dennis doesn't just have confidence in himself, he's obsessed with himself. It seems like his lack of patience for the rest of humanity stems from the fact that he doesn't feel anyone else deserves a moment of his time.
That high opinion of himself eventually leads to him dubbing himself as a golden god -- something he likes to frequently tell people. Despite the fact that no one else seems to view Dennis in this light, he will not be convinced he is anything less than a figure to be worshiped.
"You two have boyfriends? How did you not know that the reason I invited you over was to bang you?"
Dennis' true and frightening personality comes out when he is pursuing women. He sees females as nothing but conquests and when the prospect of sleeping with them is taken off the table, he regards them with nothing but contempt.
During a hurricane scare, Dennis uses it as an opportunity to try and persuade girls to come seek shelter at their bar. But when two attractive girls ask if they can bring their boyfriends, Dennis' rage is unleashed. To him, sleeping with these girls is something he is owed and for them to be uninterested is a great injustice.
Dee: "We’re not really going to kill her, so what are we going to do?"
Dennis: "Oh yeah. Oh sh*t, that’s a bummer."
When a serial killer is on the lose, Dennis and Dee decide they, thanks to a combined half a degree in psychology, are the only ones capable of bringing down the killer. In order to find the madman, they decide they must act like a serial killer -- something Dennis takes to far too easily.
After picking the Waitress as their pretend victim, Dennis lays out their plan only to be disappointed when he remembers they aren't actually going to be murdering anyone.
"I am untethered and my rage knows no bounds."
To say that Dennis has a flair for the dramatic would be an understatement. To say that he has anger issues would be an even bigger understatement. More often than not, these two qualities come together to form a frightening and impressive rage-fueled rant.
It rarely needs to be something significant that sets Dennis off and is more often a mundane exchange that unleashes his fury. When a potential buyer for his truck suggests it would make a good starter car for his daughter, Dennis snaps in a way he's never snapped before.
"Because of the implication."
To get a glimpse inside the mind of Dennis Reynolds can be a deeply disturbing experience. It's clear the kind of person who has the thoughts he has is not well in their mind. The most horrifying example is Dennis' nautical-themed theory he dubs "the implication".
Without going too deep into the extremely dark theory, Dennis seems to have no problem incorporating intimidation into his romantic pursuits. The fact that he doesn't understand why Mac finds this so disturbing is even more troubling.
"I would like to go in your room and I suspect that maybe you might say ‘no’. And yet, I also feel like maybe… you wouldn’t dare."
As disturbing as it was to hear his theory of "the implication" explained, it's even more disturbing to see him try to act on it. That is the case when the gang goes on a cruise and Dennis sees this as the perfect opportunity.
Again, Dennis might not see himself as a threatening madman, but he also can't seem to avoid coming off that way. In his mind, he is being charming, but his creepiness is dialed up to eleven which eventually sends the poor girl screaming and running away, much to his surprise.
"Dee, I swear you would be of more use to me if I skinned you and turned your skin into a lampshade."
Few people are on the receiving end of Dennis' rage as often as Dee is. While she is no saint herself, the way Dennis treats his own sister is just further proof that this man is not right in the head. So while him threatening Dee is nothing out of the ordinary, this particular threat seems maybe a bit too specific. It doesn't help his case at all when he insists he wouldn't do such a horrible thing because the smell would be unpleasant.
"D-E-N-N-I-S… the Dennis System."
For proof of Dennis' twisted mind look no further than the time and energy he puts into his plans for sexually deviant acts. If he dedicated a fraction of that to other aspects of his life, he could be a very successful man. We get a full display of the madness at work in his mind with his explanation of the "Dennis System".
This is Dennis' apparently fool-proof plan of seduction which basically includes lying to women, neglecting them and emotionally abusing them. As if that existence of the Dennis System wasn't dark enough, that fact that he proudly names it after himself should tell you a lot.