Turk looses his golf visor as they are walking away from the camera.
A man in a wheelchair crashes into a bright red Volkswagen in front of JD and Turk. A split second later there is no bright red VW or wheelchair man anywhere in the parking lot.
When Dr. Kelso quickly drinks the glass full of scotch it originally has ice in it. However, when the shot changes, there is no ice at all, which would have required him to have swallowed the ice cubes whole.
When J.D. and Sean are talking in the bar, the amount of foam in Sean's beer changes from shot to shot.