50 First Dates: precursors?

"50 First Dates" (2004) shares various similarities with Hong Kong romantic comedy "Why Me, Sweetie?!" (2003) (simplified Chinese: ?????)

In Why Me, Sweetie?!, a woman falls for a man who suffers selective memory loss triggered by his own falling in love. He repeatedly connects with her and then forgets who she is. The genders are reversed and the "rules" of memory loss are a little broader, but the hijinks of trying to woo an amnesiac are generally the same.

Details, trivia and caveats:

1) DVD cover

Amazon, IMDB and Wikipedia reference the same mock DVD cover whose headline reads "The film that inspired the Adam Sandler comedy 50 FIRST DATES!" This image exists in low quality on the web only and the claim is not repeated on official or bootleg versions of the English-subtitled DVD.

The origin of this mock cover is unknown. It doesn't seem to come from the makers of Why Me, Sweetie?! or DVD producer Mei Ah. Neither is there any record of correspondence between the makers/DVD producer and Columbia Pictures.

2) Screenwriter

In a podcast interview, screenwriter George Wing states that he drafted "Fifty First Kisses" as an original personal project, which Columbia Pictures purchased via his agent. Following "upheaval" at the studio, it gained the attention of Adam Sandler and his team, who rewrote virtually all the dialogue but left Wing's basic characters, plot and circumstances intact. Wing is the sole credited writer of the script. At 5:22 he says (emphasis added):

That has a lot to do with the fact I originated it. If you originate a screenplay that's not based on something else you have a lot more clout when it comes time to determine the credits.

Wing implicitly takes credit for the story here.

Officially there is no connection between 50 First Dates and Why Me, Sweetie?!, but between the (coincidental?) plot similarity and mock image there persists a popular opinion that one is based on the other.

I would say your instincts are well tuned, but the evidence is inconclusive. :)

It's hard to find a review of the film that doesn't compare it to Groundhog Day. For example, from Roger Ebert's opening line in his review:

Just in time for Valentine's Day, "50 First Dates" is a spin on the "Groundhog Day" notion of a day that keeps repeating itself.

Certainly the underlying premise of having to repeat a day over and over is the same, although 50 First Dates uses a slightly different plot technique to achieve this. Whether this makes it original or whether it just makes it an intelligent copy is subjective.