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.
Yuudai slowly warming up to Taisei after Taisei enthusiastically tries to become his friend could be seen as this, especially considering how awkward and blushy Yuudai is around him. After the brothers and these two have an excessive drinking night together, Yuudai loses his shirt and has to go home with Taisei's t-shirt on.