The Waitress sleeps with Dee's twin brother Dennis in "Charlie Has Cancer".
Dee and the Waitress sat next to each other in Trig class in High School but Dee does not remember her. (The Waitress Is Getting Married). Dee first officially met the Waitress when Dee and Charlie were taking Tommy Doyle (the boy Charlie thought was his son) to the mall shopping. The Waitress was mentoring a young Mexican girl as part of a Big Sister program. Charlie had tried to imply Dee was his girlfriend but Dee corrected him. (Charlie Wants An Abortion).
Charlie now manager of the bar manipulates Dee into setting up a series of circumstances that force the Waitress to go on a date with Charlie. The Waitress is in love with Dee's twin brother Dennis and Dee preys on this and makes the Waitress believe Dennis is sleeping with Mac's mom and Charlie's mom. When Dee gets a phone call from Charlie she rudely tells the Waitress to pop out of the car so she can take the phone call. (Mac Bangs Dennis' Mom). The plan ultimately backfires and the Waitress sleeps with Dennis and Dee's father Frank.
After the gang tries to sell their shares of the bar Dee manipulates the Waitress into getting her a job at the old time family restaurant that the Waitress is assistant manager of. Dee robs from the customers and refuses to refill the condiments on her table. The Waitress had to get a second job because a Starbucks had moved into the neighborhood of the coffee shop she worked at. (The Gang Sells Out). The Waitress gets manipulated into giving jobs to Charlie and Dennis as well. Dennis drinks on the job and is as lazy as Dee. Charlie calls the franchise owner who already held a grudge with the gang. He fires all of them.
Dee obsessed with Sex & The City and having few female friends blackmails the Waitress into hanging out with her and Artemis and going clubbing with them. The Waitress who is a recovering alcoholic relapses and begins drinking again. Dee and The Waitress both admit they hate the other. (Who Pooped The Bed?)
Dee and The Waitress both dated Kyle Fisher in high school. Dee becomes obsessed with breaking them up when she discovers they're engaged. Kyle actually led both women on and planned on dumping them as revenge for dumping him in high school because of his acne. (The Waitress Is Getting Married)
Dennis, Dee, and Frank humiliate the Waitress during their podcast by getting Rickety Cricket to dump dirty mop water on her. (Mac's Big Break)
Despite their many misadventures Dee cannot remember the Waitress's name.