Episode #1.7 - S1-E7
Continuity mistake: There are a load of won notes in Bok-su's front pocket when he is in the dream. When he first slaps himself, one of the notes can be seen bending forwards, while all the other notes are upright in his pocket. When it cuts to an angle from the side, the note that was shown bending forwards is no longer there, then it reappears in the following shot. (00:55:45)