So much is packed into this delightful, charming little drama that a lot of viewers mistake it for fluff. It is anything but!

The acting, writing, direction and cinematography are top notch. Its use in particular of visual metaphor is beautiful. One the surface, this is a delightful rom-com with one of dramaland's best OTPs. But underneath that, it is an intelligent and thoughtful discussion of the commodification and treatment of women in society and four women's attempts to attain self-determination. All of the female characters are intelligent, three-dimensional women (although one of them is a robot).
It's not new to have a kdrama examine our need for human connections but I feel like this is the quintessential show for exploring that theme.
I can't remember another show that I enjoyed so much on so many levels and that gave me so much joy while it was on.

I have quibbles but for the purposes of recommending a show they don't really matter. There's a perfect version of this show with a slightly-stronger final two episodes but it's rare to find perfection on television. 99% of it was perfect and that's what's important.