My ratings:

1-2 Absolutely awful. Didn't like anything about the drama, probably couldn't even finish it.

3-4 Not very good, but hey, I finished it.

5-6 Neither here nor there drama. Wasn't bad, but maybe wasn't one of my favorites. Might not recommend unless there's something particularly interesting about it.

7-8 Good drama. Had a few issues with it, but overall I would recommend this drama to a friend.

9-10 Absolutely would re-watch. I enjoyed everything about the drama and have little to no complaints. 

**It is rare that I will rate anything below 6. I tend to be very easily entertained, and I value good acting and dialogue over any other qualities in a drama. If the drama can keep my attention then it deserves at least a 6 in my opinion.