Cheers remains one of the top ten iconic sitcoms of all time. During its run, it was an absolute ratings juggernaut, cementing the careers of everyone involved in it. Ted Danson and Woody Harrelson in particular rose to super stardom out of this series.
What made the show work was the incredible array of supporting characters that surrounded the stellar main cast. But after 11 seasons on the air, a series can develop a group of supporting cast members who were far less beloved than others.
Walt Twitchel
Cliff Clavin was a breakout character on the series, thanks to the mailman's inability to stop spouting unbelievably incorrect facts at everyone. Thankfully, Carla was there to shut him down, sometimes in very violent ways. But he had rivals in other parts of his life, too.
At his post office day job, there was Walt Twitchel who appeared throughout the run of Cheers starting in season three. As aggravating as Cliff was, Twitchel was somehow even worse. Their enmity was so bad that they didn't reconcile until season nine of Fraiser.
Andy Andy
Nothing says "I love you" like hiring a killer to date someone you care about. Andy Andy was an ex-con who went to jail for killing a waitress at an Italian restaurant and Sam hired him to date Diane. He was an unsettling guy who caused problems the handful of times he appeared in the series.
The last time Andy Andy popped up was in the final season when he returned to the bar for the first time in years with dynamite strapped to his chest. It's not a great way to make friends.
Walter Gaines
When Woody and Sam worked at a party for Boston's elite as bartenders, Woody met Kelly Gaines. A young woman of wealth, she returned from Europe and her father threw an incredibly lavish party for her. Woody and Kelly fell for each other almost instantly, and would eventually get married.
Unfortunately, Kelly's father Walter wasn't happy about the whole situation. An elitist through and through, Walter was not fond of Woody and was not shy about his feelings. The young couple's love was in spite of him, making Walter an obstacle in their love story.
Robin Colcord
After Shelley Long left the series and took her character Diane Chambers with her, a new love interest was needed for Sam. Kirstie Alley was brought in as Rebecca Howe, Sam's new pursuit though the chemistry wasn't the same. Still, Rebecca brought in new opportunities for comedy.
Her obsession with finding a wealthy man led her to chase a lot of unfit suitors like Robin Colcord. He used Rebecca's love as a means of collecting information on the company she worked for as part of a hostile takeover bid. That's not how you treat someone you love.
Gary
Sam had his own rivals in the world of Boston bars, specifically Gary's Old Towne Tavern. Gary's bar was more successful and more popular than Sam's, something that got under Sam's skin constantly. Their annual Bar Wars face off allowed them to vent their frustrations on each other.
These events also gave the crew at Cheers some of the few times they actually got one over on Gary. Their rivalry continued until the final season when Harry the Hat tricked Gary into demolishing his own bar.
Harry The Hat
Harry was a mainstay of the early seasons of Cheers. The con artist would stop by the bar to runs scams on the employees and patrons, only to get tossed out by Sam when he caught him. He would often take advantage of Coach, in particular. Harry the Hat was played by Harry Anderson, who fans might know better as Judge Harry Stone on Night Court.
As often as he would scam the gang at Cheers, he would also help them on occasion but that was more because he didn't want anyone else running a con on his pigeons.
John Allen Hill
Cheers was downstairs from an upscale restaurant called Melville's run by John Allen Hill. Much like Walter Gaines, John was an elitist who looked down on Sam and the rest of the gang from the bar. In Hill's case, he looked down on them both figuratively and literally.
Any time he walked down the internal staircase that connected the two businesses, Sam knew he was in for a rough day. Complicating things further was the strange, hate sex filled relationship John had with Carla.
Loretta Tortelli
Carla Tortelli was the rough around the edges waitress that kept Cheers running and Cliff quiet. Well, as much as anyone reasonably could. The bane of her existence was her husband's new wife, Loretta. A dim witted, vivacious blonde, she was the opposite of Carla in some truly terrible ways.
Loretta also insisted on coming by the bar a lot in the early seasons, rubbing her relationship with Carla's ex-husband in Carla's face without realizing she was doing it. They did develop a bit of a bond as time went on, though. There was only one person in Carla's life worse than Loretta.
Nick Tortelli
The scumbag ex-husband of Carla isn't just the worst person who showed up in the bar, there's a distinct chance that he was the worst person in Boston. Nick rampantly cheated on Carla despite having multiple kids with her, then left her for Loretta.
Despite all of this, Carla still felt a strong attraction to Nick until she was finally able to break his spell and move on. Nick continued to hang around, though, even starring in a brief Cheers spinoff called The Tortellis. It had a very short run, possibly because their leading man was such an awful person.
Professor Sumner Sloan
The most unlikable person in the entire run of Cheers showed up in the very first episode. Sumner Sloan was an English literature professor who left his wife to be with Diane. In the pilot episode, they stop at Cheers on their way out of town. Sloan abandons her there when he decides to go back to his wife, destroying Diane's life. Sam helped her rebuild her life only to have Sloan reappear and convince her to pursue her writing career.
Sam and Diane pause their marriage for six months until she returns, which she doesn't do until the season finale six years later. Sloan's selfishness brought Diane into Sam's life and took her out of it.