So, you know how everyone thinks that the Top is his totem, but in the beginning he mentions that it’s actually Mal’s? Well, you see, if it’s not his totem, then it’s not going to properly work for him. Cobb’s totem is his wedding ring. Whenever he’s dreaming, he has a wedding ring on because, as he says, in his dreams, they’re still together. In reality, he’s not wearing a ring. During the last scene of the movie? He’s not wearing a ring. BAM, REALITY.