Because you're too damn mule mean, that's why. You always was.
6 seconds sound clip from the The Shootist movie soundboard.
You can hear this line at 01:04:04.266 in the DVD version of the movie.
Quote context
[...]
- Woman, I still have some pride. A man should be allowed his human dignity.
- I spent $3.00 on the train here. One-way.
- You and Dobkins are two sides of a counterfeit coin.
- I'll pay you back. I'll pay you both ways.
- I'll not be remembered for a pack of lies.
- Because you're too damn mule mean, that's why. You always was.
- You bastard. May you rot to death!
- 'Twas blighted affection that made him exclaim 'Oh, willow, tit-willow, tit-willow'.
- And if you remain callous and obdurate, I shall perish as he did, and you will know why.
[...]