Where's Mom Moment

A situation where you are expecting something for a long time, and not only do you not recieve it, but you also get no explanation.

(Derived from the infamous scene from Avatar: The Last Airbender where Zuko asks, "Now... where's my mother?" and the fans get NO RESPONSE after waiting 3 SEASONS.)

Megan: "...Hey, didn't Mr. Sommers promise us donuts this morning?"
Alan: "Yeah. He probably forgot. Talk about a 'Where's Mom Moment'."