I know I may be nitpicking here, as all dramas has its own flaws, which essentially boil down to differences between Western and Eastern cultures.

Firstly, while the overall premise is very entertaining, I can't help but feel that the whole "vampire" trope could have been left out, without the plot being too affected. Early on in the series, there were several times where I forgot that the FL is a vampire, only to be reminded of it when the plot needed it. I know this is based on a webtoon, so I can't comment on it's faithfulness to it's source material.

Secondly, I personally feel like there are some very questionable ethics at play here. Sometimes I feel like the vampire plot point was only shoehorned in, so the FL could harass the ML as much as possible. She wants to be with him so she can feed from him, and to do that she must manipulate him as much as possible. Not only does she want to "cure" the ML from his mysophobia, she also contacts his estranged mom against his will. There's also pet abuse (a goldfish dies from clearly improper care).

There's also the love triangle which makes me slightly uncomfortable, because the other love interest is a massive creep, who not only keeps private photographs of the FL, but also feels that he has the authority to make decisions for her several times.

Overall, this series feels... weird. I'm definitely going to watch the second season to see where everything ends up, but my hopes are not as high as they could have been.