The second couple is very much the more adorable one that the first couple is a waste. Although, it's difficult to enjoy simple plots like these with questionable actions after the rise of Manwha. I used to enjoy simple yaoi like this, but now, it's pretty cliche to read. Perhaps it's really just my age.
•chapter 1-2: rich boy who is bad at expressing his love towards his teacher crush. •chapter 3-6: cold, expressionless friend of the previous couple x a straight personality playboy.