I loved the unhinged scenes every now and then, the actors put all their might into them. Then comes the ending, to say it's bad is an understatement. It was done purely for shock value. It doesn't serve any other purpose, not even an artistic/poetic one. Straight up wasted which really unfortunate because the drama was decent.

Note that this drama is 16 episodes + 4 extra. The extra episodes were completely useless and irrelevant to the main story, just some cases of the daily life of a loan shark and can be skipped.