Man pulling out the cuckoo metaphor in front of Rei is vile. Definitely does make him sick. When Rei saw the cuckoos he saw it as how he hurts the family he was adopted into and does not want to be a person who grows through taking advantage of others. For this scumbag of a father he sees himself as a cuckoo and says “Yup, that’s me, and I’m happy with that”. It’s second nature for this piece of shit.
Love the use of the “We’re not so different, you and I” cliche use here, it makes sense AND shows the growth our protagonist has gone through ever since the metaphor.