Recently, in a thread on the subreddit r/movies, redditor u/StPaulStrangler asked movie lovers to name actors they didn't buy for a second in a particular role, and people really came through with some passionate examples!
So with that in mind, here are just a few of the most popular responses shared:
1. Mark Wahlberg, The Happening (2008)

"I did not buy Mark Wahlberg as a high school science teacher."
Here's a glimpse at the performance:
View this video on YouTube
2. Oscar Isaac, X-Men: Apocalypse (2016)

"I adore this supremely talented man, but Apocalypse was horribly miscast."
Here's a glimpse at the performance:
View this video on YouTube
3. Reese Witherspoon, Walk the Line (2005)

"She felt really out of place at the time, but even more so now."
Here's a glimpse at the performance:
View this video on YouTube
4. Keanu Reeves, Bram Stoker's Dracula (1992)

"Keanu is a wonderful human being and a good actor, but that man should not have been cast in this. Poor guy."
Here's a glimpse at the performance:
View this video on YouTube
5. Adam Sandler, The Longest Yard (2005)

"Adam Sandler as an NFL quarterback."
Here's a glimpse at the performance:
View this video on YouTube
6. George Clooney, Batman & Robin (1997)

"George Clooney is a great actor, but he really missed the mark in this movie."
Here's a glimpse at the performance:
View this video on YouTube
7. Mila Kunis, Oz the Great and Powerful (2013)

"I’m sorry, but her voice stuck out so badly. With the popularity of Meg from Family Guy at the time, it was too hard not to associate the two when hearing her voice. Like, if Patrick Warburton was a primary character in a movie, you'd immediately call back to every voice he has done, as his voice is just as recognizable."
Here's a glimpse at the performance:
View this video on YouTube
8. Jai Courtney, Terminator Genisys (2015)

"He didn't resemble Michael Biehn even slightly. From his face, his hair, his voice, and his build — this one annoyed me the most. The character grew up in a war zone eating garbage for dinner, but now he's somehow jacked like he lives in the gym and eats steaks? They got everything wrong with his casting. It was so off-putting, he might as well have been playing a different character. At least Emilia Clarke vaguely resembled a young Linda Hamilton."
Here's a glimpse at the performance:
View this video on YouTube
9. Nicole Kidman, The Northman (2022)

"I was totally immersed in that film, and all of a sudden she shows up with a bad accent, and it took me out of that reality and made it feel like a movie. At least they made her character hatable too."
Here's a glimpse at the performance:
View this video on YouTube
10. Matthew Broderick, Godzilla (1998)

"But that’s probably because I like him as Ferris Bueller so much. In the back of my mind, I’m thinking, No way a kid who thought driving a car in reverse would decrease the mileage on a car could be an NRC scientist!"
Here's a glimpse at the performance:
View this video on YouTube
11. Cameron Diaz, Gangs of New York (2002)

"I really didn’t buy her in that. I actually do like her and can name more than a few movies that I enjoyed her in, just not this one."
Here's a glimpse at the performance:
View this video on YouTube
12. Robert Redford, The Great Gatsby (1974)

"Coolest guy in the world as an extremely fuckin' weird Jay Gatsby."
Here's a glimpse at the performance:
View this video on YouTube
13. Zooey Deschanel, The Hitchhiker's Guide to the Galaxy (2005)

"I love her in so many things, and she really SHOULD have been right, but she was a terrible Trillian."
Here's a glimpse at the performance:
View this video on YouTube
14. Dwayne "The Rock" Johnson, Jungle Cruise (2021)

"It's not as if there's one set archetype for a Disney Jungle Cruise skipper, but The Rock definitely doesn't fit the bill. Someone once suggested Oscar Isaac for the role, and I can't help but think that would have been a better choice."
Here's a glimpse at the performance:
View this video on YouTube
15. Emma Watson, Beauty and the Beast (2017)

"I’m just gonna say it: Emma Watson as Belle. I’m sorry, but they either needed to give her more time to perfect her vocals, hire a voice double for her singing parts, or hire an actual Broadway actor for the part, as Paige O’Hara was when she took the role."
Here's a glimpse at the performance:
View this video on YouTube
16. Rami Malek, The Little Things (2021)

"For me, this one really stood out. He plays a hotshot detective and just never really fit the role, for whatever reason. I've liked him as an actor previously, but everything seemed to miss in this film."
Here's a glimpse at the performance:
View this video on YouTube
17. Jesse Eisenberg, Batman v Superman: Dawn of Justice (2016)

"Jesse Eisenberg as Lex Luthor. As soon as I heard the casting, I knew it would be awful, and it was."
Here's a glimpse at the performance:
View this video on YouTube
18. Emma Stone, La La Land (2016)

"La La Land is good and Emma Stone is good in it, but a hopeless dreamer/failed actor is the wrong part for an A-list megastar with a uniquely beautiful appearance."
Here's a glimpse at the performance:
View this video on YouTube
19. Leonardo DiCaprio, Don’t Look Up (2021)

"It was impossible for me to take infamous Hollywood playboy Leonardo DiCaprio seriously as a nervous, neurotic professor."
Here's a glimpse at the performance:
View this video on YouTube
20. Gerard Butler, Geostorm (2017)

"In the same movie, Jim Sturgess played his brother, who was a politician, and I think they should've traded their roles."
Here's a glimpse at the performance:
View this video on YouTube
21. Owen Wilson AND Reese Witherspoon, How Do You Know (2010)

"Owen Wilson as pro baseball player? Reese Witherspoon as a softball star? I don't see athleticism in either of them."
Here's a glimpse at the performances:
View this video on YouTube
And finally:
22. The entire cast, House of Gucci (2021)

"Adam Driver to the lesser extent, and Jared Leto to the greatest."
Here's a glimpse at the performances:
View this video on YouTube
You've read their picks, but now it's your turn! Is there an actor whom you had an impossible time believing in a specific role? Share in the comments below!
Note: Some responses have been edited for length and/or clarity.
H/T: r/movies.