It's sweet, but what's more it's unexpectedly dynamic in its storytelling. Characters and relationships can develop. We can learn things that overturn our mental view of certain people. Not bad for a series of three-minute episodes.
Oh, and it's also funny.
There are two main characters, plus a modest supporting cast. Habahiro Hige is a lovable fat man who loves marshmallows. They're so important to him, in fact, that he's oblivious to the lesser things in life, e.g. sex and romance. If a girl tried to seduce him, he'd be uncomprehendingly aghast and would stop her from shedding her bra. He's a thoughtful, good-natured gentleman without a mean-spirited bone in his body... but goodness me, he can be dense sometimes.
The other main character is Wakabayashi Iori, his deadpan 24-year-old colleague who fancies him rotten. It's a combination of love, warm-hearted affection and some kind of fetish. Watch ep.4 and tell me that's not a fetish. Wakabayashi's single-minded enough that her antics would probably count as sexual harassment under normal circumstances, but of course it's never enough. Everything she does is too subtle for Hige. You wouldn't put it past her to enter the room nude... except that that wouldn't work either. The only successful tactic with Hige would be to come out and confess your feelings to his face, but unfortunately our heroine has a bit of a mental block about that. Yes, that's right. Wakabayashi's a sensible, intelligent lady in almost all respects, but she's a bit odd. She knows it, too. She has a complex about the word "normal" and she gets sufficiently unsettled when separated from Hige that she's capable of starting to hallucinate him.
Together, though, she and Hige are a charming combination. They're both very likeable and their bizarre sparring never stops being entertaining. Besides, the show doesn't mind separating them to keep things fresh and they're both fully capable of carrying scenes and episodes on their own, e.g. Wakabayashi's girl's night out in ep.5 or Hige's marshmallow factory visit in ep.4. (They know him there. They call him "the fairy" and they've realised that he worships the factory as his god.)
The supporting cast are fun too. My favourite is Wakabayashi's brother, whose behaviour is odd enough that trying to nail down his problems would be a fairly long discussion. He clearly has a sister complex, but beyond that? What he is, though, is funny. Any episode with him is likely to be one of the most entertaining. Then there's MIO5, who's a bit on the big side (i.e. curvaceous) and decides she also likes Hige. She's Wakabayashi's rival. She's better at being direct, which is all-important with this particular target, but Wakabayashi knows more about marshmallows.
It's not a sex comedy. There isn't even fanservice, despite Wakabayashi's best efforts. You could safely show this to your mother. Oh, and sometimes there's a live-action bit at the end where two of the show's voice actresses pad out the running time by showing ways of cooking marshmallows. You might not think a series of three-minute episodes would need that, but there we are.
It's based on an online manga that got over 20 million views and this anime adaptation. Technically it's a workplace comedy, although that's not a major element. It's still just a handful of three-minute episodes, mind you. It's light-hearted fun that'll make you smile without really adding up to very much... but that's okay. Not everything has to be a big deal. It's nice. I'm fond of the characters. It has story development. I'd recommend it.