The tone is without a doubt the most notable aspect of this series, what truly makes it work. This is a show about parenthood, and while that subject can be used to create fantastic drama, regardless of the rather unusual familiar situation our protagonists are faced with, there is not really not that much drama, or rather melodrama. This depends on your personal experience, of course, but you probably will not cry while watching this series, nor will you laugh out loud, despite the fact that there are some funny moments scattered throughout the show. This is an anime that does not try to milk your emotions; never, at any point, did I feel I was being manipulated.
There is such intelligence at play in regards to every scene, even the ones that one would catalog as the most likely be to big moments. Any moment with Masako, Rin's mother, could easily have been exploited and taken in a a varied number of directions, but they are always kept very subdued and tactful, such is the case of the scene in the cemetery. The show is dotted with moments like this that feel incredibly rewarding to the viewer because their sincerity is so pure and does not impose itself upon them.
I must declare my admiration for the subtlety with which this anime follows and rejects conventions. Daikichi, throughout the series, displays clear attraction towards Yukari, but despite making this fact known to the viewer, there is not much of a follow up to it. Same thing happens with Rin's mother (spoilers!); nothing ever comes out of her besides the fact that she cannot bear to rise Rin as that would heavily class with her life ambition. And I have to applaud that the series does not really cast down judgement on her for that. Daikichi does, but that is his opinion, not the series' itself. (end of spoilers).
The way these events are treated, plus the lack of very significant dramatic developments that go beyond Rin catching a cold that does not pose an actual threat to her life (it does give the pair a scare, but that's rather normal) make of this series a sweet slice of pie out of someone's life. What we see as mundane -going to work, taking your child to school, working extra hours- is shown repeatedly through the series. At first Daikichi has trouble, as anyone adjusting to such a dramatic change would, but once he gets used to it the series moves on to something else. The ending is externally unceremonious, but internally enriching for Daikichi, which does sum up the entire tone of this series.
I believe that this might be a bit of a drawback for some people. At some points I lamented that there was not much more drama, I feared that if the series got too comfortable then I might get bored; however, that never happened. I was entertained and intrigued throughout my entire viewing experience. I consider that some people might see the relative lack of fanfare within the series as a lack of commitment or aversion to taking risks, but I would disagree with that notion.
In any case, this is a perfect series to get comfortable with and let it wash it over you like a cleansing wave: I ended every episode with a large and satisfied grin, and I suspect that will be the case for most people capable of appreciating this show's intentions.
