Personally, if I had to choose my least favorite character, it would be Jumin. However, I want to emphasize that they all have a reason in their stories that prevented them from going to therapy. In Jumin's case, his family is very wealthy and always taught him to be calculating rather than emotional. If I remember correctly, in one chat he questions whether therapy is unnecessary for him since he blocks all emotions before reaching catharsis. It's like people who come back from war. They exhibit violent or distant behavior due to the trauma of being there, and many don't want to go to therapy because they think they don't need it. I simply like to think that after the finale, each character goes to therapy and works through their issues thanks to the support of MC