I hate to say it, but Cary Grant just doesn't seem comfortable in this role! Doris Day said he was very private and that, while the filming relationship was amicable, there wasn't much give-and-take and I think it shows in the film.
It ends up not being very memorable—I'd seen this before and barely remembered anything. It's a nice enough diversion but it's not one I would return to.
Audrey Meadows is so so good in her supporting role and I enjoyed Gig Young in this, too!
And it does have some scenes set in an automat and automats are one of my favourite things ever so that's cool. (The running gag with Meadows mistaking Young for Grant's character utilises the automat well).
Not the worst, but really not great.