The temple on the last page literally says Rumi Noona above the statue on the wall. I don't know if the mc made the place or what. Maybe ordered his subordinates to make it, but thats hilarious contrasted with the serious red haired girl.
He's so cute about it, but I totally sympathize with the main character. He just wants to be left alone to enjoy peace and quiet, buddy. I'd react the exact same way and even watching makes me really uncomfy.
F in ch 45 is probably referring to mbti, as in the more emotional personality type. F 감성 폭발 직전 meaning an emotional person is about to have an emotional outburst towards you.