There's a very common motif in the series that I can't find here. Although most episodes feature it, I only remember some ocurrences:

• Jack sees his dead father on White Rabbit//OK, sorry. It doesn't play on this scene.
• Several times on Meet Kevin Johnson;
• Eloise's face is revealed at the end of The Lie//Sorry, again! What the hell!
• A custodian tells Desmond not to tell anyone he found Faraday's equipments (16:02; 16:55); after either Desmond or Widmore says something to each other (33:52) (Jughead).
• It plays at 0:12 here: [1]