I disagree with you... so you mean Gun Wook as Sun Young’s brother don’t have the right to harass or scare a loser, playboy whom dumped a lovely girlfriend in such an immature nasty way like a totally jerk? Tae Sung had everything in his life but just lacking a motherly love & he’d chosen to be a loser, the rebellious child. Who fault is it that he doesn’t want to grow up and be a responsible & worthful man? And if you feel pity for him for not getting the girl at the end, then it’s just his karma for dumping Sun Young. Also nobody is blaming him for Sun Young’s suicide/death but he can’t get away without the grief feeling for an indirect cause here.

Try to re-watch and analyze... Compare to GW's suffering since young who do you think who suffered most? TS separate with his mother only & GW separated with his parents, lived with the Hong for ONE whole year then suddenly got thrown away like a trash and his parents died. The Hong family did gave him love and he did love them too (esp. President Hong). The more you love a person, the more you’ll come to hate that person if he/her betrays you. If I would be like GW "if and only if" it would be a big damage for the revenge to make it with whole family. If you try to look and analyze the other characters you’ll know. I felt sorry for TR & MN too & JI at the end. But if it’s based on the story of this drama I sympathize with both TS and GW who were victims of the evil Witch. But I feel more pity for GW from beginning till the end, who’d lost TWO families & his last source of comfort ie. Sun Young. I deeply feel for poor GW, thrown away BOTH times, then, in childhood, and at the end - his running away, wounded, from this family, repeats itself,..

I feel that GW tried to 'harass' them, to 'rattle their golden cage' and to attack their pride and lack of affection, more than to push things too far like towards death... he surely was sorry for what happened to the older brother, and he didn't want to drown TS, only to scare him... as for innocence, ... now, there is an entire discussion about who is innocent , and who is not innocent... (of course, if only he knew!... he surely was 'stabbed in the back'). Just look at the last episode, at KNG's acting and you'll know how GW really was and then, look at the last episode, and see who has a moral conscience, and who doesn't.