- Are you serious?
- Yes, sir.
- A good idea? Take another look.

6 seconds sound clip from the The Bridge on the River Kwai movie soundboard.

You can hear this line at 01:30:18.631 in the Blu-ray version of the movie.

Quote context

[...]

- How's he behaving?

- I must say, he's been most reasonable since we took over.

- I wonder what he's thinking.

- I haven't the foggiest.

- Thanks, Reeves.

- Right, sir.

- What do you think? Quite a challenge, isn't it?

- Sir, are you convinced that building this bridge is a good idea?

- Are you serious?

- Yes, sir.

- A good idea? Take another look.

- You don't agree that the men's morale is high? That discipline has been restored? That their condition has been improved?

- Are they a happier lot or aren't they?

- Yes, sir, but...

- They feed better and they are no longer abused or maltreated.

- That's all true.

- Well, then honestly, Clipton, there are times when I don't understand you at all.

- I'll try to make myself clear, sir. The fact is what we're doing could be construed as forgive me, sir, collaboration with the enemy. Perhaps even as treasonable activity.

[...]