Loved this movie!

The movie has only one important fault, for me: it's too long.

Not the fault of the movie is that the sorts of gags it uses, and the specific kinds of reactions (including facial expressions and vocal mannerisms) that characters evince when they find themselves in incongruous and absurd situations have been copied so many times that looking at this movie once again, they can seem "old"---but of course they're not, or they were not to the same extent, when the film was made.

Possibly the fault of the movie: looked at very roughy and broadly, the movie has only one (kind of ) joke, and the whole film amounts to just a marvelous set of variations on a single theme, the same joke.

What is really overlooked by many or most people posting here and in the reviews here, is the unmatched quality of the script and in particular the dialog. Hepburn's stream of quips, for example. You have to actually think about each of them to really get it. A lot of her lines, and Grant's, do not involve slapstick at all; they are funny to think about, even right then, in the moment.

And as for Hepburn, who else could even have delivered her lines in that manner, pronouncing the words as fast as that and making them intelligible? One after another, bang, bang, bang. Zip, zip.

No one.

Hope that wasn't too long.