Andy Fiddler is supposed to be a salesman for dental hygienic products and equipment however he has horrible teeth! His bottom teeth are extremely crowded, stained and yellowed. He would not be a very convincing salesman in real life.
When Andy is eating his hamburger in the diner, Vann is drinking from a glass, the two straws are white when Vann is holding the glass, at one point when the glass is placed on the table the straws are clear. The glass is also repositions itself a few times.
When Vann pulls out in front of Andy who has stolen his car, Andy puts the car into a spin. The shots then alternate between the interior of the car where we can clearly see the windows are either down or clear to an exterior shot where the windows of the car are tinted and closed.
The second time Andy is told to go to a specific place to meet up with the dealer, he gets out of the car and gets back in without telling Vann where to go. Somehow Vann seems to know where to go right when Andy gets back into the car.
After Vann drives and knocks Booty into the telephone pole Vann can be seen driving on for a couple seconds afterward and past cars on the right. Those cars are gone and Vann is only a few feet past the telephone pole when he stops the car and gets out to "talk" with Booty.
When Vann cuffs Andy in the car and goes up to visit Manny Cortez, the car is off with the keys clearly in the "off" position (which can be seen when Andy turns the stereo on). A minute later, Andy glances over at the steering column to find the keys on and the engine somehow running.
In the diner where Kane gives Andi the "taste", the opening of the bag is folded to the right. When Kane pats the bag before leaving it's folded to the left and then it's shown folded to the right again.
The goof item below may give away important plot points.
At the end of the movie, Vann gives the lieutenant his gun. In the next couple of scenes however, Vann gets a gun pointed at his head and in turn, pulls out his own gun which he had already handed over.