Go to the scene where Kurt says he'll take the last GoodBurger to go. He takes a bit out of the burger and then drinks the rest of a container of pop. He then lowers the cup behind the counter and you can hear the sound of the cup hit the floor. But if you look in the reflection of the door just as the sound of the cup hitting the ground is heard, you can clearly see Kurt still has the cup in his hand! Talk about bouncy floors!