my drama ranking:
10-9 — they are the best, i love the plot, pretty much every episode was good, interesting main characters
8.5-7.5 — they had small stuff that i didn't like, maybe a character that was irritating, maybe some discrepancy in the plot, maybe the ending wasn't the best. but i still like them very much
7 — enjoyable and entertaining but i wasn't captivated by them, might rewatch
6.5-6 — mostly dramas that were enjoyable, but their plot/genre wasn't something i particularly liked or i liked first part but after some plot-point it become boring, won't rewatch them
5.5-4 — i liked some of it, but could live without watching it, mostly boring
anything that i would rate below 4 was dropped by me after first few episodes