Revealing: In the swimming pool scene, when David is sitting at the bottom of the pool, you can clearly see a scab on one of his knees.

Continuity: After the pool incident when David is writing letters. Monica is looking over the letters that David has written. There's a point where you can see that she's still holding at least 2-3 sheets of paper but when the camera shifts back to the writing there's only one in her hand. There should be more than one paper in her hand.