On the 18th hole, Fred's opponent Charlie hits his tee shot on the fairway. When Charlie is shown making his second shot, he is not shown hitting the ball on the fairway; he is shown hitting the ball from the same tee box on which he made his first shot.
When Fred checking with Wilma to make sure she checked the Ruble's house to make sure there was nothing else Barney borrowed from Fred, he opens up a can of soda with the can opener in a close up shot of the can opener on the table. Then when Fred says "Oh he does, does he?," the soda can is gone.