I watched She Was Pretty first. I'm now currently viewing Kill Me, Heal Me.
I personally think that Park Seo-joon and Hwang Jung-eum have better chemistry as siblings than they did as a couple. I really like their interactions in KMHM...I think that might be because I like his character more in this show than I did she was pretty.
But..I can't help but wonder why his character has all that information on Do Hyun....