Over the course of its 10 seasons, Friends had more than a few notable guest appearances. Some of these cameos elevated the story, while others couldn't save a less than desirable storyline. For the most part, however, these guest spots were a delight. The actors brought the necessary tone for their storylines, even when that required them to be in both comedic and serious during certain moments.

These guest stars also worked well opposite the main cast. Sometimes that meant simply acting in of the other characters. In a few cases, it meant stealing a scene (or episode) and being part of some of the funniest and best moments of the series. Some of the guest appearances were especially special because of how viewers knew the actors outside of Friends. Maybe they were simply a big name, maybe they starred on another favorite television show, or maybe even the smallest cameo signified a crossover with another show.

The best cameos had viewers laughing throughout an appearance and made them the shortest of scenes even years later. In some cases, an entertaining performance could even make viewers ignore the fact that the six friends mentioned some actors by name or should have recognized them.

Here are the 4 Cameos That Hurt Friends (And 21 That Saved It).

Saved: Jason Alexander

Jason Alexander guest starred as Earl in "The One Where Rosita Dies". Phoebe encountered the office manager when she had a temporary job selling toner over the phone. He told her he was going to end his own life, and she went down to his office to stop him.

Bringing on Alexander was a treat to sitcom viewers because he played George on Seinfeld and Friends' Courteney Cox appeared on that show. It was a treat for fans of both shows without making it some convoluted crossover that wouldn't have made any sense.

Saved: Jane Lynch

Jane Lynch appeared as a realtor, Ellen, in "The One Where Estelle Dies". Monica and Chandler checked out the house next to their new one and ended up running into Janice.

Lynch's guest spot wasn't that big of a deal. Neither she nor it were over the top. Instead, it was a fun cameo, one that allowed fans to recognize the person in the scene without taking away from the actual plot. That was what was needed for the scene since it was one of the final episodes of the series.

Saved: Gary Oldman

Gary Oldman appeared as actor Richard Crosby opposite Joey in "The One With Monica and Chandler's Wedding". Joey had to contend with the other man's habit of spitting when he enunciated. By the end of their time together, they both needed towels to dry off after each take.

It was an amusing side plot to the wedding and its hijinks. Oldman was fun to watch in the role acting opposite Matt LeBlanc, not just when they were filming for their movie, but also when Richard had consumed too much alcohol to work.

Saved: Craig Robinson

Craig Robinson appeared in "The One With Princess Consuela". He played a clerk when Phoebe went to change her name following her and Mike's wedding. His rapport with Lisa Kudrow's Phoebe was on point.

His guest spot was brief, but memorable, especially considering the episode was a busy one. Furthermore, the importance of his scene was for Phoebe to realize she could change her name to anything. That plot's focus was on Phoebe's name changes (and then Mike's). The episode also included Monica and Chandler showing Joey their new house and Rachel getting fired and then offered a job in Paris.

Saved: Christina Applegate

Christina Applegate guest starred as one of Rachel's sisters in multiple episodes of Friends. The character was pretty awful (even compared to season 1's Rachel and their other sister Jill) and didn't change between appearances. However, Applegate was fun to watch in the role and opposite the main cast.

That was why, even though the character didn't need to return when she did, it wasn't that bad. She worked well with the cast, especially Jennifer Aniston and David Schwimmer, which was important since her most memorable moments were with their characters.

Hurt: Jean-Claude Van Damme

Van Damme guest starred as himself in "The One After the Superbowl, Part 2". Rachel asked him out for Monica, but he was interested in Rachel. Though Monica did end up going on a date with him, he only went because he thought he'd get more out of it than he did. She refused, but he still brought up the possibility of being with both her and Rachel together before he left.

Friends' version of Van Damme wasn't a good person, nor was there anything particularly funny about the plot. Both the character and cameo felt unnecessary.

Saved: Winona Ryder

Winona Ryder appeared in season 7 as Melissa, Rachel's sorority sister with whom she shared a kiss in college. Rachel used that experience as an example that she could do crazy things.

While seeking confirmation from Melissa that it happened, Rachel learned how much it had meant to her friend. Melissa hadn't moved on and had even hoped that something could happen between the two women. Rachel had to let her down. Ryder displayed just the right amount of eagerness after Rachel kissed Melissa again to remind her of their past.

Saved: David Arquette

David Arquette appeared as Ursula's stalker in "The One With the Jam". He mistook Phoebe for her twin, and then Phoebe tried to cure him of his obsession with her sister. Though she thought she was successful and even dated him, she soon learned he was still following Ursula.

Malcolm wasn't a very sympathetic character, nor was this the best storyline. However, the way Arquette played him brought the proper amount of humor to the scenes even though stalking is a serious issue. Because Friends was a comedy, it wasn't going to be treated as such, but another actor could have made it worse.

Saved: Hugh Laurie

Hugh Laurie didn't have many lines, but his delivery of the ones he did was pretty much perfect in "The One With Ross' Wedding". He played the enger next to Rachel on the plane to London. He had to listen to her detail her and Ross' history, as she planned to stop Ross' wedding.

From his request that she tell him if she planned to continue tapping so he could take a sedative or give her one, to him putting headphones on when she started talking about Ross to him telling her the truth about her actions, this was one of the best guest spots in the history of the series.

Saved: Brad Pitt

Brad Pitt's appearance was clearly a big deal, and the series didn't shy away from acknowledging that and why with his character. He appeared as Will, Ross' high school friend who hated Rachel in "The One With the Rumor". The Thanksgiving episodes are among Friends' best, so fans always them. Therefore, Pitt's guest spot in one had to be memorable for all the right reasons -- and it was.

Pitt was entertaining opposite the entire cast as Will ed everyone for Thanksgiving. His reaction to Phoebe's appreciation of his looks and his disdain for Rachel were his most memorable moments of the episode.