Haven't you anything better to do than ride around in that little, red sash making yourself obnoxious?
5 seconds sound clip from the She Wore a Yellow Ribbon movie soundboard.
You can hear this line at 00:09:40.381 in the Blu-ray version of the movie.
Quote context
[...]
(BUGLE SOUNDING IN THE DISTANCE)
- Lieutenant, the post is closed.
- Sorry to spoil your outing, Miss Dandridge.
- Oh, come on, don't be a spoilsport.
- Because I wouldn't trust you to take me on a picnic last Sunday, now you're hazing Mr. Pennell.
[...]