When a segue is expected, yet doesn't happen.
An expected Flashback or Fantasy Sequence fails to appear. Medium Aware characters will comment on this, otherwise awkward silence occurs as nothing happens when a character stares into space (because normally other people can't see thoughts). The in-universe version gets the same reactions after a segue, when it is revealed that only the audience saw it and not the other characters. If the audience is left out while characters reminisce, then it's a Noodle Incident. Contrast with Imagine Spotting & Third Person Flashback.
Examples:Live Action Television
Indexes: Comedy Tropes, Fourth Wall, Flashbacks and Chronology