Right but this is due to the messed up relationship between his mom (who was a mistress from the looks of things) and his dad. In the flashback, it showed him overhearing his mom complaining to his father on the phone saying he’s your son too, we had a child together and you don’t do enough for us blah blah blah and his dad hung up on her and it seems like he might’ve cut her off. So Sihyun is under the impression that she got greedy for his love and money and he cut them off. Then, Idk when the dad took him in, because as we heard him on the phone present day, it sounded like he was talking to either his father or stepmother and they were saying “Don’t get cocky just because you finally did a decent job at work, that’s the least you can do to repay us for letting you be apart of this family” so he is just like hollow and feels inferior and unlovable and he wasn’t raised in a loving, healthy environment whatsoever so you’re right when you say he’s dumb but it mostly just applies when it comes to feelings because he never felt like his were worth expressing or his wants and desires were worth exploring (which is why he doesn’t even know what he likes.)

Do ppl really not get the ml is dense asf? Like he literally is dumb and it’s not really his fault but like also it is, but besides that MC is smart and eventually will have to figure it out for the both of em but Ik he won’t let ml live it down. So till then we gotta wait patiently till they get together (which I think will be satisfying lol) can’t wait for the new seasonn >_<