What's the worst performance you've ever seen by a good actor?

[Everlong]

Just about every actor has a stinker or two here and there, even the best in the world. So, what would you say are some of the best examples of awful performances given by great actors?

[Daz]

Pretty much anything Al Pacino's done in the last ten years. Maybe longer.

[flock u]

as soon as I read the title I instantly thought of Robert Deniro in Rocky and Bullwinkle

[Romo]

Sean Penn in All the King's Men

[Ali]

Nicolas Cage.

Just... Nicolas Cage. He's done so many bad movies that people forgot he's actually really good, but to be honest, he's the best thing about 99% of the "bad" movies he's in! I love Nic Cage for that reason. He's almost always fun to watch.

But there is one movie I've seen where he is outright BAD: "Bangkok Dangerous". Usually, if a movie's bad, Nic Cage is at least animated and over-the-top. Here, he's sleepwalking, he's just as bored as the audience, and it's a chore to watch. It's honestly kind of sad.

I hear that "Left Behind" is an even worse case of this, but I haven't seen that yet.

[DBSoT]

Matthew McConaughey in Fool's Gold or Failure to Launch. Let's just hope we all forget these ever happened.