If a show doesn't have a rating then I most likely don't remember what I thought about it or just straight up forgot to rate it o-oops  Some of these I watched a really long time ago, no matter how recently they were added to my list.

-I'm not very critical of what I watch. So my rating for shows are kind of all over the place. My ratings are based on enjoyment, not quality or critique.
-If it's above a 5, I enjoyed it.  If it's below a 5, I... still might have enjoyed it just not nearly as much I could have, or I might have forced myself to watch it. Who knows.
-Some of my 8+ ratings are also inaccurate. Some of them could actually be rated higher or lower. There's actually very little difference in how much I enjoy the dramas I rated 8+...
-Whenever I rewatch something, I adjust my rating accordingly.

TBH, I'm just trying to keep track of things I've watched for future reference cause I like watching dramas with my friends. It's hard to remember what all I liked if I don't keep a list...