In "the Gang Gives Back," Mac says that Dee looks like Big Bird in her canary yellow pantsuit.
In "Mac is a Serial Killer," Mac and Dennis accuse Dee of looking like Larry Bird. She counters that they look like Larry Bird, which doesn't have the same effect.
Subverted in another episode, where Dee predicts that the guys are about to call her a bird again. Mac retorts that he was going to say "fish" this time, because her eyes are so far apart.
In "Who Got Dee Pregnant?", Dee wears an angel costume to a Halloween party, but the gang calls it a bird costume, and it gets progressively more bird-like in each retelling of the story, until, in Mac's version, she's an actual ostrich.
In "Mac and Dennis: Manhunters", Dee, along with Charlie, becomes ravenous after eating what she thought was human meat. While eating meat sandwiches, she starts to peck at her food like a bird.
In "The Gang Saves the Day," Dee imagines that Josh Groban sings a song about how beautiful and not like a bird she is.
Dennis's creepy fixation with sexual conquest, to the point of being a borderline date rapist
His D.E.N.N.I.S. System is a method for getting women to fall in love with him using lies and emotional manipulation.
In "Fatty Magoo vs the Aluminum Monster," Dennis says, "I'm not going to take no for an answer because I just refuse to do that, because I'm a winner and winners... we don't listen to words like 'no' or 'don't' or 'stop!' Those words are just not in our vocabulary."
Dennis states in "The Gang gets a Boat" that women always put out on boats because of "the implication." He has to repeatedly insist that he wouldn't actually rape the women on the boat.
In "The Storm of the Century", Dee accuses Dennis of raping girls in the bunker.
In "The Anti-Social Network," Dennis says, "I could be a man with a fistful of hammers, a trunk full of duct tape and zip ties." In "The High School Reunion part 2", he reveals he actually has a trunk full of duct tape and zip ties. He's fetching them because he's angry that a woman rejected him.
In "How Mac got Fat," Mac comments, "Dennis always tells me, 'Never let someone else's resistance keep you from getting what you want.'"
Dennis's practice of recording all of his sexual conquests without their knowledge is brought up in a number of episodes. In "Charlie and Dee Find Love," he claims that he has running cameras in his bedroom at all times.
In "Charlie Rules the World," Dennis brags about "entering" a date with "almost no resistance." In his video of the evening, he's also seen pushing her head down to crotch level. Though he gets it in return when he enters the astral plane and British Dennis, after giving him a haircut and some sage advice, does the same thing to him.
In "Reynolds vs. Reynolds: The Cereal Defense," it's revealed that Dennis has several bench warrants for sexual misconduct.
In "Paddy's Pub: Home of the Original Kitten Mittens," Dennis tells The Lawyer that he'll sneak into his house while his wife is sleeping and "ease into her real nice" so both spouses will be cheating on each other.
In "The Gang Squashes Their Beefs", Frank wonders why Dennis always tries to get people to sign a contract. Dennis says the fact that it is in writing means they have to do whatever they agreed to.
In "The Gang Goes to Hell", Dennis' attempt at flirting through invoking "the implication" gets him tossed into the brig.
Other Gags
Mac's delusions of being tough, his Catholicism and his homoerotic fixation on the physiques of other men.
Sweet Dee's cars constantly being stolen and destroyed by the rest of the gang. Lampshaded in "Reynolds vs. Reynolds: The Cereal Defense."
The gang apparently only owns one VHS cassette and simply tapes over it repeatedly. Whenever they show a new video, snippets of past videos from previous episodes bleed out around the edges.
No one in the Gang remembers ever meeting the Waiter, despite their numerous encounters.
