In Dave's office when he and Lisa confess their affair to Mr. James, Dave's necktie is loose and not loose between shots.
Joe tells Bill that his homemade stun gun will send 300-400 volts thru a person's body at 4 amps, resulting in "instant temporary paralysis." In reality, 0.2 amps is more than enough current to kill a human.
When Lisa pours water into her cup to make tea it is very obvious that the water is not at all hot.