'whoops-a-daisy' originates from the playful expression 'up-a-daisy,' which was used to encourage children to get up after a fall.

'Up-a-daisy' transformed into 'whoops-a-daisy' as a more playful and informal version, eventually becoming a common expression in English.

Initially, it was used to encourage children to rise after a fall, but over time it evolved into an expression of mild surprise or dismay.