Your motives were good, even though your reasoning was perfectly idiotic!
7 seconds sound clip from the Blackbeard's Ghost (1968) movie soundboard.
You can hear this line at 01:01:18 in the Blu-ray version of the movie.
Quote context
[...]
- Well, Jo Anne, that's exactly what happened!
- Besides, didn't you say you believed in the pirate?
- Besides, I believe in him as a metaphysical image, not some stupid, sticky-fingered goop.
- Well, that's exactly what he is!
- Hurry up, Coach. It's beginning.
- Okay.
- I shan't bother you any more. I want you to know that I understand perfectly.
- Your motives were good, even though your reasoning was perfectly idiotic!
- You regard me strangely, son. Something amiss?
- Money? Money... Oh, the odd flimsy I removed from the purse of your bookish wench.
- Why should that stir your ire?
- Because it belongs to the little old ladies!
[...]