Yoo Ah-in would have been a perfect fit for Jo In-sung's role in the movie 'Possible Love'. He was originally part of Lee Chang-dong's circle.

I believe Yoo Ah-in could have expressed all the acting nuances that Jo In-sung couldn't.
Especially Yoo Ah-in under Lee Chang-dong's direction—he is so raw. If it weren't for the Yoo Ah-in drug scandal, it would have been him.
I found Jo In-sung's acting very disappointing.