Psychopath Diary is a 2020 South Korean television series starring Yoon Shi Yoon, Park Sung Hoon, and Jung In Sun. The series follows a man who witnesses a murder and takes the diary of the killer, only to wake up with amnesia and believe that he is the killer himself.

Park Sung Hoon plays the role of Seo In Woo, the real serial killer. In Woo is a calculating and intelligent man who is able to manipulate others to get what he wants. He is also a master of disguise, which allows him to get away with his crimes.

Sung Hoon's performance as In Woo is one of the highlights of the series. He is able to perfectly capture the character's cold and calculating nature, while also showing his vulnerability when he is forced to interact with Dong Shik.

In Woo is a complex and well-developed character, and Sung Hoon does an excellent job of bringing him to life. His performance is one of the reasons why Psychopath Diary is such a compelling and entertaining series.

Here are some of the things that I liked about Park Sung Hoon's performance as Seo In Woo:

He was able to perfectly capture the character's cold and calculating nature.
He showed the character's vulnerability when he was forced to interact with Dong Shik.
He was able to make the character both believable and entertaining.

Overall, I thought that Park Sung Hoon did an excellent job of portraying Seo In Woo in Psychopath Diary. He is one of the reasons why the series is so compelling and entertaining.

Here are some other things to keep in mind about Psychopath Diary:

The series is a mix of comedy, thriller, and mystery.
It is a fast-paced and engaging story.
The characters are well-developed and relatable.
The acting is top-notch.

If you are looking for a fun and suspenseful drama to watch, I highly recommend Psychopath Diary. It is a well-made series with a great cast, and Park Sung Hoon's performance as Seo In Woo is one of the highlights.