Responses
I don't know why he is like that, but I also believe that Ms Doh stole his work. It was just too suspicious that she was the person responsible for the new art. She was working for them before and didn't have art like that, her style was different, the reason they were looking for new artists was because they wanted something different than what she offered...
But even if it turns out to be her art there is something about her that I don't like...
Yay! you have the same paranoia like me as well. Hahahaha. I also find kind of suspicious Ms Doh.
I have a feeling that Ms. Doh (who may or may not be Taesoo's ex-girlfriend) stole Taesoo's art; the one that she's currently getting credit for from Mr Hwang. I can't help but remember that one chapter were Taesoo said that he's going to put his art online. And then a couple of panels later, Mr. Hwang's subordinate had discovered new art, but they couldn't find who the owner was. Some more panels later, Doh was seemingly identified as the person responsible for that new art.
Maybe she was never the one who made it? Maybe it was Taesoo, and now Taesoo discovered that someone has been using his art against his permission and getting credit for it? (I might just be too paranoid about Ms. Doh, though. I just can't trust her.)
That, or Taesoo saw that his ex-girlfriend (not Ms. Doh) was getting married? It is the season for marriages after all. Maybe there are some lingering feelings left?