The Treasure of the Sierra Madre (1948)

Revealing mistake: When Howard and Curtin chase Dobbs, they pass a dead donkey which is obviously breathing, and the rope used to tie its legs together is visible too.

Visible crew/equipment: In the scene When Dobbs is panicking as he searches for the body of his not-so dead partner, who he had tried to kill the night before, he stumbles left and right. The camera pans a bit to far revealing the studio lot, building and fence, and a crew member sitting by a truck or machine.

Continuity mistake: When Humphrey Bogart dunks his head in the watering hole, he leans over far enough that his hat is almost entirely submerged. In the next shot, he sets his hat down beside him and only the front portion is wet.

Trivia: Director John Huston has a cameo as the white-suited man who gets increasingly irritated when Humphrey Bogart repeatedly begs him for money.

Gold Hat: We are the Federales... You know... The mounted police.
Dobbs: If you're the police, where are your badges?
Gold Hat: Badges?.. We ain't got no badges. We don't need no badges. I don't have to show you any stinking badges.

Dobbs: This is the country where the nuggets of gold are just crying out for you to take them out of the ground and make 'em shine in coins on the fingers and necks of swell dames.

Howard: Ah, $25,000.00 is plenty as far as I'm concerned. Enough to last me out the rest of my lifetime.
Dobbs: Sure. You're old, I'm young. I need dough and plenty of it.