Well, this is a really common plot device in Korean dramas... first hating each other (whatever the reason) and then fall in love...
The most famous example of it, of course being Boys Before Flowers (the original version is the Japanese one, it's the best, check it out)
Shinning Inheritance
Another Miss Oh (this is a gem!)
Cheese in the Trap
Secret (this is a melo, but it's great! the hate level is really high here)
Prosecutor Princess
Falling for Innocense
Master's Sun
She Was Pretty
Goong
