These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Hilarious in Hindsight: In Episode 5, Ui's mom embarrasses Ui by comparing Kazuma to her brother Hajime, talking about Ui being so clingy to her brother, and jokingly warning Ayumu to hang on to Kazuma before Ui takes him. Later in the series, Ui actually starts thinking of Kazuma like an older brother for awhile during a period of angst, then Tsumugi tells Ayumu not to worry Kazuma too much and hold him back in the process, and later when Ayumu asks Ui if she likes Kazuma, she replies by asking Ayumu if he's worried about losing his brother to her if she did get together with Kazuma.