The Waitress (It's Always Sunny in Philadelphia)

Charlie Kelly openly stalks The Waitress, and keeps a journal of all her activities and whereabouts day to day, but Dee steals it in return for a favor from The Waitress. It is likely he has begun a new one although Charlie has stated that he "has copies" of the original. On occasion, he has hired other people to stalk her and report her whereabouts. The Waitress has issued several restraining orders against Charlie, but amends them to allow Charlie to come within a fifty-foot radius after many of the tasks Charlie completes for her, including putting vitamins in her shampoo, testing her food for poison, and killing rats for her apartment go unfinished, and The Waitress realizes that Charlie is valuable to her life as he is the only person who cares about her well being. She also gets jealous when Charlie finds an interest in a new woman, demanding to know who "that bitch" is.

Charlie goes to great lengths in order to woo The Waitress, including trying to impress her by demonstrating his paternal nature by pretending to raise other people's children. He also fabricates a story about him having terminal cancer when he sees her wearing a Lance Armstrong bracelet. He also attempts to connect with her by pretending to be an alcoholic so he could continue to spend time with her at Alcoholics Anonymous, where he continues to guilt her into being his sponsor. The pair share an enjoyable night together at the beach, frolicking and holding hands and falling asleep in each other's arms. But in the morning The Waitress reveals she was high on Ecstasy and doesn't remember any of their encounter.

Charlie once proposed to The Waitress, but she declined.

In the end of Season 12, Charile invited The Waitress over to show her a presentation he made on where her life is going. He continues to explain how her life is over and time is ticking so she should have a kid with him. After a brief argument, Charlie responds to her question of, "Why don’t you find someone better?!" with, "There is no one better." This prompts the two to have sex.

In Season 13, Charlie and the Waitress' relationship is explored, with Charlie becoming increasingly distant from her due to finding her annoying and "a total bitch." Despite her breaking up with him after having an affair with the Dennis sex doll, she continues to appear in episodes taking place before and after Dennis returned to Philadelphia, such as serving as Dee's rival during the Ladies Beats Boggs reboot challenge and going to the Super Bowl without Charlie.

In Season 14, the Waitress made a guest appearance when Charlie recalled a series of events in the form of a 40s noir film. The Waitress was using a cherry poisoning scheme to consume alcohol behind her AA representative's back and earn some money due, but Charlie found out. She ended up poisoning Charlie with a cherry pie, claiming that they were "getting too close," implying she still has feelings for him. Charlie dismissed her, however, realising the pie was poison. He thought drinking a shot of bleach would cancel out the poison, but ended up vomiting all over her. Before she could skip town, she was arrested by a police officer (by Dee dressed as a police officer in Charlie's memory of the story) and taken to jail. A large amount of the story was likely not altered and simply made up by Charlie, heavily implying he still thinks about her romantically long after she left him.

Dennis does not care for The Waitress whatsoever; however, she is notably infatuated with him. When together, she seems to forget herself and follows Dennis blindly and will do most anything to get his attention; some instances even involve her making decisions against her better moral judgment. Her most extreme cases of trying to grab Dennis's attention include being Charlie's sponsor for Alcoholics Anonymous, grinding on homeless people, and sleeping with Frank. On several occasions, Dennis has used her undying love for him against her, mostly to blackmail Charlie into doing whatever it is Dennis would like. He has slept, flirted, dated, and been in overall close sexual contact with The Waitress in order to do said blackmailing, usually involving "climbing up the ranks" of Paddy's, getting out of Charlie work (earlier in the series) or general tomfoolery.

Throughout the course of the show, Dennis has slept with The Waitress several times, of which he records their sex, giving it a "one star" rating in terms of enjoyability and fun.

Mac has a detached relationship with The Waitress outside of trying to sleep with her in order to upset Charlie, on account of Charlie smashing one of Mac's "Project Badass" tapes. This is later revealed to be untrue, as the tape Charlie was smashing was actually Frank and The Waitress's sex tape that Charlie mistakenly watched. Mac and The Waitress actually have only engaged in "hand stuff."

The Waitress sleeps with Frank in order to make Dennis jealous of her. She does this under the guidance of Dee, who is being instructed by Charlie, in order to get The Waitress (through a convoluted plan) to like him. Unbeknownst to anyone for a long time after, Frank records their sex. His toupée falls off during their love-making session. She has sex with Frank again on a plane during the Ladies Beat Boggs reboot.