When a performance doesn't work in a movie, an audience's first reaction is usually to blame the actor. However, this isn't always entirely fair.
Sometimes, a script is so awkwardly written that not even a multi-Oscar winner could make it sound believable. Sometimes, a director guides actors towards a vision that sounded better in their heads.
Finally, we have to face the painful truth that sometimes they should've gone with a different actor. No matter how talented and versatile an actor is, they'll eventually find a role they're not right for.
Unfortunately, these stars found that out the hard way.