That moment where no particular wish came to Yuu-kun's mind, it felt a bit like the onset of personal stagnation... but only a teeny tiny bit.
It's less that he's content to not do anything, but more that he is starting to understand the bliss of a mundane life with Chiyo on a deeper level. In appreciation of such heartfelt sentiments, he walks back home with Onee-chan, back home to whatever wonders a new tomorrow might bring to those two wholesome dorks. At least, that's what this idiot thinks.
And that is nothing else but a W. Lesgooo