- Why don't you sit down and relax?
- I'm perfectly relaxed standing up.

4 seconds sound clip from the The Best Years of Our Lives (1946) movie soundboard.

You can hear this line at 00:29:27.500 in the Blu-ray version of the movie.

Quote context

[...]

- She's worked two years in a hospital. She knows more than you or I ever will.

- Cigarette?

- Have you forgotten, Al? I don't smoke.

- Oh, sorry.

- It's all right, darling.

- It's frightening.

- What is?

- Youth.

- Didn't you run across any young people in the Army?

- No, they were all old men like me.

- Yes. It's terrible to be old, isn't it?

- Why don't you sit down and relax?

- I'm perfectly relaxed standing up.

- Is there such a thing as a drink in this house?

- I'll see.

- We haven't got enough bacon for Dad's breakfast. I'll to go out first thing in the morning and try to get some.

- Is this all the liquor we have left?

- Gosh, I'm afraid so.

- I wish he'd given us some warning he was going to get here today.

- Don't worry, Mom.

- I mean so that we could have gotten in some supplies of things.

[...]