When Movie Clichés Attack

Here's a scene that's as frequent as it is unlikely:

Person X approaches person Y to confess a sin or mistake (say, adultery).
X: "I've got something important to tell you."
Y: "Well, I've got something to tell you, too."
Y tells something that makes it blatantly obvious to X that this is not the right time to make the confession (say, Y reiterates an undying love for X). Dialog continues as follows:
Y: "And what did you wanna tell me?"
X: "Oh, nothing."
Y will never wonder why something that was called 'important' 20 seconds ago is suddenly 'nothing'.

Earlier movie clichés