I'd add Fumiya to the list of "wasted potential" as a best friend character to the MC.

Sasuga dropped the ball with him, IMO. Sometimes I feel that the thing Shuu told Natsuo regarding Hina's feels should've came from Fumiya instead, which would've been a much trustier source. Instead we get a "Well, I didn't not know." I'm like...bruh... Or how he never once talks to Natsuo about what was Hina's answer after that, but we both know why Sasuga can't do that :)

It's still funny that Shuu's actually the one saying this to Hina later on. I know a lot of folks hate his guts for leading Hina on & lying to Natsuo back then which definitely dealt a blow towards his resolve to be with Hina. But he kind of redeemed himself in my eyes for a while now as he became quite supportive of Hina's affection for Natsuo & wants her to be happy.