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1.
A typically sarcastic or apathetic exclamation made when a miscalculation or mistake has been made; most often, this applies when an individual has missed some cue to stop, thus creating a useless or bothersome excess.

Generally, it applies to any benign mishap. But in the ideal context, it deals with "going overboard" with a task, often completing something that should have been stopped long ago; also applies to an overestimation of needs, thus creating or getting much more of an item than is needed.

The origin of this phrase is from a variety of Cap'n Crunch cereal: The "Oops All Berries!" branding featured no rectangular yellow cereal pieces, only the round multicolored "berries" as introduced in Crunch Berries.

Widely regarded as the authority on Captain Crunch consumption, Curtis Cartwright explains the phrase:

"What oops? You put ALL BERRIES n***a? WHAT? Like, somebody just hit the button, was like, Oops, N***a, all berries! F**k it! Put that s**t on the shelves!"

Evident in Cartwright's interpretation, there is also an sense that in saying the phrase, it is a suggestion that the use of the now excessive something has become appropriate. It's already been made or done, so the idea of using the excess anyway is implied in the uttering of, "Oops, all berries..."

If the mistake is humorous or absurd, then the exclamation can be accompanied by throwing one's hands up in an exaggerated shrug and an amused expression of sarcastic confusion.
Roommate 1: Hey, how many of those cases of Bawls did you get?

Roommate 2: Like, ten.

Roommate 1: Are you kidding me? There's no room in the fridge for that, no way we're gonna drink it all!

Roommate 2: Oops, All Berries!

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I ended up working all night to finish that assignment, but class got canceled. Oops, All Berries!

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Friend 1: I asked Amy to go out with me, and she shot me down. She said she wasn't really interested and I misread the signals.

Friend 2: After you booked the restaurant and got a cake and everything? Oops, All Berries... Mind if I have some of that cake?