I've been watching k-dramas, c-dramas and anime for more than a decade. 

I give k-dramas and c-dramas separate ratings. This means that I rate c-dramas are based on all the c-dramas I've watched. Same with k-dramas :)

My ratings are based on my personal enjoyment and rewatch value. C-dramas that I rated <= 5 is suitable to watch in the background