Continuity mistake: When Bugs says "Gin! You lose!" at the end of the card game, he is wearing a cowboy hat and gun holster, but when we see Bugs in the next shot, the hat and holster have gone.
Continuity mistake: When Bugs hits Sam on the nose with a pea-shooter, you can he is wearing his cowboy hat, but when Bugs leaves the saloon in the next shot, his hat has disappeared.
Bugs Bunny: Your move first, Sam. C'mon, pick a card.
Yosemite Sam: All right! Don't rush me. I'm a-thinking... and my head hurts.