This memory is from Eternal Summer Episode 1.

What he learns:
- Samezuka tradition is to see if anyone can beat the captain
- Mikoshiba challenges Iwatobi to a random relay, which Haru is naturally prepared for
- apparently so are Makoto and Nagisa. these guys...
- He tried to teach Nitori a bit more. Good to see their relationship has improved.
- He was still trying to get a reaction out of Haru and Haru was still being a butt.
- But hey Samezuka still won.
- WAIT MIKOSHIBA MADE HIM CAPTAIN? WHY? Didn't he piss off Samezuka?
- Apparently, this is what Mikoshiba meant by him taking responsibility for his actions.
- He's still not comfortable with it though...
- Hmm, Mikoshiba was talking about a new impressive member showing up...
- And of course his friends HAVE TO GO AND EMBARRASS HIM IN FRONT OF HIS KOUHAI. WHY DOES HE LIKE THOSE GUYS AGAIN?

What this means:
- +100 awkwardness over leadership roles
- why the hell would Mikoshiba choose him?