Like the boss, this show has some mental issues. It's kinda bi-polar. Is the writer or PD the one responsible for "Another Oh Hae Young?" I can see some similarities in the contrast of the humor and dramatic parts, same actors as well (I count 7, including cameos for both dramas). Unfortunately, Park Hye Soo does not have the charisma and chops of Seo Hyun Jin. Her acting is disjointed, it's as if we're seeing two different characters on the opposite spectrum. Seo Hyun JIn was able to come up with a character that was whole and complex and funny and sad at the same time.

The reason it's not working as of episode 4, is that Ro Woon could not complement and play off Hwan Ki's character. There's no chemistry and thus, no redeeming factor, which annoys me and could not make me care for either character. I so desperately want to like Park Hye Soo because she was cute in Age of Youth. She's just all over the place in this drama. Again, 2 different characters being portrayed by the actress and not a complex, well-developed one, as the character should be.
She is annoying and nosy and sometimes she gets on my nerves!  Is it really the character or it's the actress acting?  I am giving this until ep5 and decide if I will drop or continue eventough I love Yeon Woo Jin here! 
I find her attitude to be double edged- while I adore her persistence and find it refreshing as someone as already said, I find her lack of awareness a red flag. She refuses to see anything around her or pick up on social clues that tell her where boundaries lie. I understand her background or rather the way she thinks her sister's life ends makes her rather tunnel-visioned, but her complete disregard to the implications her actions have on others is horrifying. To the end, she doesn't seem to understand just how close she came to ruining the secretary's life- her character probably would have killed herself if it was even slightly different. 
Secondly, I really hope that all characters- including her and the male lead's father and so on come to terms with his disorder and learn how to behave. The way they are around him is atrocious- the character must be in so much pain because of them! Yes he keeps his "office" closed off! IT'S HIS HOME TOO! I don't see everyone rushing to the co-CEO's house and barging in like it's their right!! The things they criticise him for are ridiculous and I hope to god they improve!
@HighQualityTrash - I totally agree with everything you've said! Dramabeans just posted this: Introverted Boss takes a week off to rewrite and regroup. So maybe there is hope yet?
i hope the female lead isn't going like to be like Song Se Dong in Blade Man in which she's being super annoying and feels like she's replacing the male lead .
I get the idea that the writers wanted two characters with completely opposite characteristics to show the contrasting introvert/extrovert theme (opposites attract, romantic relationship in the works, positive change in both characters ensues, etc) but I felt maybe they made Chae Ro Woon a bit too strong from the start. I'm fine with her character in a sense that I predicted she'd be a bit headstrong and somewhat confrontational, which would eventually force Hwan Ki to break out of his shell, but they took it to another level in my opinion. Judging from the first few episodes, her actions and behavior were off-putting to me because as a viewer, I'm already aware that Hwan Ki has issues with social anxiety and even though it's a given that Chae Ro Woon doesn't know about that side of Hwan Ki, or anything about him for that matter, it's a bit uncomfortable to watch her continuously provoking him, being somewhat of a bully, and pushing him to the edge. Not to mention invading his privacy, instigating internal company issues like with the secretary, and not feeling any remorse for her actions. It's always about how she feels and what she wants while everyone else is wrong. Her prejudice towards him makes it hard for me to consider her as a possible love interest for him or a likeable character in general because she refuses to be open-minded about anything. It's obvious her sister's death and the mystery behind it was traumatic for her and is now preventing her from making any rational judgements or even try to see the bigger picture when it comes to Hwan Ki because he's the CEO of the company where her sister worked and she's already blaming him for her sister's death. But it's not just her though, just about everyone in this drama so far seems to be judging Hwan Ki when they don't know anything about him, it's just that she goes the extra mile in harshly criticizing him.

This is only the beginning though and like many dramas, it takes a few episodes for some characters to change and develop. I'm not going to stop watching because of her character because I'm a fan of Yeon Woo Jin and was looking forward to seeing him in a new drama, but I hope that with the newly revised episodes coming up, there will be some positive changes that can help move the drama in a positive direction. I want to like her and understand more of why Hwan Ki likes her so much as well, but so far I can't see why he would be so smitten with her when they haven't shown any redeeming qualities for her character.
LOL. She scares me a little. -_-
I'm late to this party at I just started the show but I honestly can't stand her. She annoys me to no end, like whenever she is on screen I feel like I wanted to punch her. I don't really understand her character or why we should look pass that and like her. 
aaggghhhhh I can barely watch the drama bc of her... I love everything else about the drama and at first it was okayy with her behaivour that way but lately she makes me want to break the screen......I ship her sister with the main lead more TT_TT wouldve been a drama that I would love more tbh 
I personally think she's improved immensely since the beginning of the drama... the re-write really helped. I really appreciate how she's moved past trying to make him less introverted and more like Woo Il, and is not trying to do things that it make it more comfortable to step up on his own. I mean, her ideas still aren't perfect and she sometimes misses the point of want he wants... but she's genuinely trying to accommodate and be helpful to him now... not push him to be something he's not
The revenge stuff was too heavy compared with the previews. I think it's a double edged sword. They dropped the revenge which was good but they dumped the sister's backstory almost entirely in that one episode and heavily implied she had a crush on Hwan-ki and the two of them together looked so good. It's a tough one because the older sister is played so well by the actress and her character "fit" Hwan-ki so much better.
Not to extend of annoying and slightly cute for me..She's the key of this drama

I dropped this series because of her.   Her character ruined the drama. 

I think 'm the only one but i found her really cute, really annoying characters are cute to me for some reason

 The White Truck of Doom :

I dropped this series because of her.   Her character ruined the drama. 

I continued because of her lol