someone is disappointed (≧∀≦)
It's not that easy.
If you just focus on the '' psychological '' profile of Kim Dan you'll understand that all his behavior makes sense.
Dan is in a vulnerable place mentally by default because of his constant feeling of guilt. He always felt like a burden, and because of that he tends to be really harsh with himself to the point where he doesn't even stands up for himself (same way he was with JK ). He's not just gonna leave Seoul and be with his sick dying grandmother, all happy and living la vida loca while forgetting everything that happened including his guilt and pain. Dude's got balls for not dealing with a severe depression at this point.
And here I thought he'd have his shit together be all jacked up and show that horse bitch some karma