15 TV couples who didn't get along in real life

The INSIDER Summary:

• Problems can arise when on-screen couples don't get along in real life.
• Some of the most famous on-screen couples had trouble behind the scenes.
• The best examples include Ross and Rachel from "Friends" and Luke and Lorelai from "Gilmore Girls."

Acting out make-believe characters is what actors do. So if they're cast in a TV show alongside an actor they're supposed to be in love with, they get on with the job of acting.

A TV couple spends long hours together on set. They're thrown together constantly, there are countless love scenes, there are bust-ups, and there are occasionally fun times. Sometimes the two actors involved fall in love in real life, while other times they become friends.

What’s the worst that can happen? Well, the worst that can happen is that they don’t get on, argue, and grow to hate each other. That's a problem, though, since they're supposed to be in love, and this can mess up the tension between their characters.

The true professionals grin and bear it. They keep acting and doing their job, even if they don’t like it. Other times, actors complain and demand their their TV significant other be written out of the show or replaced, or that their scenes together be limited. Some actors who hate their costars have been known to walk off their shows, throwing things into chaos.

Here are 15 TV couples who actually despised each other:

SEE ALSO: Why Matthew Perry would say no to a 'Friends' revival

15. Mulder and Scully — "The X-Files"

Mulder and Scully hate each other? The answer to that seems to be yes. Back when the original series of "The X-Files" was airing in the 1990s, Mulder (David Duchovny) and Scully (Gillian Anderson) were victims of the show’s success.

They were forced to work long hours together. As the fateful saying goes: Familiarity breeds contempt. Duchovny has gone on record saying that there were times when they were so sick of each other that they fought constantly and got to the point where they could not stand to be in the same room together.

While the intimate relationship between Mulder and Scully is not heavily emphasized in the plot lines, it is always in the background of the show. Even though Duchovny and Anderson could not stand each other, the chemistry between their characters is skillfully maintained by two talented actors.

Still, it’s hard to imagine the arguments and tension that went on when the cameras weren’t rolling. Apparently, things were less tense when the duo filmed the reboot of the series in 2016. Fans were delighted to learn that the show would return mid-season in 2018.

14. Puck and Santana — "Glee"

Mark Salling and Naya Rivera hate each other. Their characters on "Glee,"Puck (Salling) and Santana (Rivera) have an on again, off again love-hate relationship that is always interesting to watch.

In real life, Salling and Rivera were involved in a relationship during the first season of the show. It seems that their turbulent on-screen relationship mirrored their off-screen one. After the first season wrapped and the cast went off on summer break, Salling began “cheating” on Rivera with other women.

Rivera responded by keying and egging his Lexus, which pretty much meant that the love-hate relationship was now permanently based on hate. After that, the writers made certain that the two had few scenes together.

Almost no one saw what was coming next: In 2015 Salling was arrested on child-pornography charges. The one person who clearly was not shocked was Rivera. She has gone on record saying that after her experiences with Salling, she was not at all surprised.

13. Charlie and Kate — "Anger Management"

Selma Blair makes no secret of her hatred for Charlie Sheen. In "Anger Management," (Sheen) and Kate (Blair) are therapists and anger-management specialists who compete against each other on every level. It’s a true love-hate affair.

Eventually, the inevitable happens and the two become lovers. Now, Sheen has a reputation for being difficult at the best of times. Just ask "Two and a Half Men" creator Chuck Lorre. So, no one expected that, after his exit from Lorre’s show, he would behave any better on the set of "Anger Management."

Some say that Blair complained about Sheen’s behavior on set. It seems that perhaps she might have been annoyed by the fact everyone had to sit around waiting for him to learn his lines. She maintains that an angry Sheen confronted her and insisted that she be sacked.

She also claims she learned she was being fired via a text message from Sheen himself. Sheen, of course, denies that, and says that the show simply took a different direction. Blair threatened legal action, but nothing came of it.