saying

[m3gan]

why do people say "whoops a dasies"?

[Quizmonster]

Its earliest appearance in print was in the 1860s as 'upsa-daesy'. It appears to have no connection with the flower, as such, but the 'ups' or 'oops' part is just a natural exclamation suggesting surprise. (We also use it when we nearly bump into someone, for example.) When suddenly lifting a child, the same element of surprise - and delight for the 'victim' in this situation - is present. As for the rest of the word, it might just as easily have been 'dandy', 'dinky', 'doozy',  or any other similarly rhythmic sounds.

[IndieSinger]

Right, that's it, from now on I'm saying "Oops-a-dinky".

[Sequin]

http://www.guardian.co.uk/notesandqueries/query/0,,-1110 ,00.html

[Quizmonster]

Go for it, Indie! My partner and I decided long ago that saying "Oops!" when almost colliding with someone was silly and that thenceforth we would say only "Squedge!" Sadly, we haven't kept it up, however.

The version 'up-a-dazy' dates back to the early 18th century. If, as your link suggests, this were truly a word brought to Britain by Danish invaders...ie presumably prior to the Norman Conquest...it took the best part of a millennium for any of us to use it, Sequin! Seems rather improbable to me.