There are so many great sitcoms out there, and within each television series, fans have their favorite and least favorite characters. Besides the regular stars, though, there are also sometimes guest stars who make surprise appearances on shows, and there are faves and non-faves out of these people, as well.

They may play themselves for a brief moment, or they may be a character who sticks around for quite some time. Either way, these guests are not always exactly welcomed. In fact, the 16 that are listed out down below ruined entire episodes! From their bad acting and silly plotlines to the way they clearly didn’t mesh with the main characters, their moments within these popular sitcoms were not the best parts of the stories… not at all. So, here they all are, ladies and gentlemen: the guest stars whose roles actually ended up ruining these great TV shows.

16 Aisha Tyler As Charlie Wheeler On Friends

Friends is one of the most celebrated TV shows of all time, and since it focused on a young, fun and attractive group, there were many love interests over the course of the series. One of them was Dr. Charlie Wheeler, a woman that, for some reason, both Joey and Ross dated.

She was around for nine episodes, and she was played by Aisha Tyler...who could’ve stuck with voicing Lana on Archer and hosting Whose Line Is It Anyway.

15 Rashida Jones As Karen Filippelli On The Office

It was a dark time on The Office when Jim transferred offices and began dating Karen Filippelli. The fact that she was into first-person shooter games, the fact that she wore pantsuits and the fact that she distracted Jim from Pam are all reasons why Rashida Jones’ time on this hit series was not the best.

14 Kathy Bates As Jo Bennett On The Office

Another actress who guest starred on The Office was Kathy Bates, and while this woman has had some iconic roles, playing Jo Bennett was not the greatest for her or for fans. Her company bought Dunder Mifflin, and on top of that, her character also was friends with Nancy Pelosi, from the South, owned huge great Danes, drove a Cadillac, survived breast cancer and could fly planes… That’s a lot of unnecessary information.

13 Pamela Adlon As Pamela On Louie

On Louis C.K.’s show, Louie, Pamela Adlon plays a friend and eventual love interest named, well, Pamela. In real life, she helps in producing and writing this series, and based on her character’s crass behavior, sarcastic lines and bad mood, it would be best if she stuck to the off-camera work.

12 Lizzy Caplan As Julia Cleary On New Girl

Another no-nonsense supporting character on yet another sitcom was Julia Cleary on New Girl. This character, who was portrayed by actress Lizzy Caplan, was a lawyer that Nick dated, and she flat-out told Jess that she did not like her… which was definitely not going to make fans like her... at all.

11 Megan Fox As Reagan Lucas On New Girl

Before he found his true love, Nick seemed to have had a type, as he also dated Reagan Lucas; she was a tough pharmaceutical sales rep who ended up moving into Jess' room. Yes, it was sad without the main star around, but couldn’t a different person have filled this void?

10 Linda Cardellini As Abby Day On New Girl

One more New Girl guest star belongs on this list: Linda Cardellini, as Abby Day. Abby, Jess’ sister, was supposed to be a black sheep and a bit of a wild card. And while Cardellini had memorable roles on shows such as Freaks and Geeks, Bloodline, Dead to Me and Mad Men...she didn’t here.

9 Martin Mull As Gene Parmesan On Arrested Development

Arrested Development is a crazy show with so many plots and characters to keep up with, and it's true that fans may say that it has just enough of all of that, meaning that really random characters are not needed. Martin Mull, for instance, who pops up and surprises everyone as Gene Parmesan is not vital to the story at all.

8 Jason Sudekis As Schmitty On Always Sunny

On a similar note, there is The Gang from It’s Always Sunny In Philadelphia. These central characters are key to the wildness of this show, and at times, side characters come in and add some interest, such as Gail the Snail and Cricket. So why did a big name (Jason Sudekis) need to pop in as an old friend (Schmitty)?

7 Lindsay Lohan As Danielle On That ‘70s Show

When there is a good thing going within a sitcom series, a guest star can throw a wrench in that...especially if the star is a really big star. That is what happened on That ‘70s Show, when Lindsay Lohan played a (thankfully short-lived) character named Danielle.

6 Katie Holmes As Naomi On How I Met Your Mother

While this is an iconic episode and tradition within the world of How I Met Your Mother, the actual portrayal was not great; Ted always wore the same Halloween costume and went to the same party, to try and meet back up with Naomi (Katie Holmes), but they actually weren’t a good match.

5 Anna Gunn As Amy On Seinfeld

Seinfeld is a classic television series, and over the years, it had some great guest stars. Anna Gunn was not one of them. She did appear on the show, as a character named Amy, but it was not as acclaimed of a moment as, say, any part of Breaking Bad.

4 Natasha Lyonne As Anyone On Portlandia

Portlandia is known for having different celebrities who appear in skits with Fred Armisen and Carrie Brownstein, and over its course, Natasha Lyonne has been in five episodes, as characters such as Wife, Carrie's Friend, Laura's Friend and Madison… characters who could have been left out of the series.

3 Aubrey Plaza As Beth On Portlandia

There is another actress who (unfortunately) appeared on Portlandia: Aubrey Plaza. Her dark and moody thing that she always seems to have going on may have won some people over on the TV show Parks and Rec, but it was not needed, yet again, in three episodes of this sitcom.

2 Justina Machado As Darci Factor On Jane The Virgin

On Jane The Virgin, Rogelio met Darci Factor, a matchmaker, and the two ended up having a baby together. While this show was known for over-the-top drama and magical realism and musical numbers and such, the big personality that Justina Machado brought about was maybe just too much at times.

1 Brooke Shields As River Fields On Jane The Virgin

Another character associated with Rogelio on Jane The Virgin was River Fields. She was an actress who got her eyebrows burnt off, her toe bit off by a wolf and half her face paralyzed after a kick to the face.

Maybe it was all of that or her interest in Rogelio or the fact that she, too, was played by a big name (Brooke Shields) that made her not the best part of this show.