1: Waste of time: it's not even worth writing about these.
2) Very bad: Shows that adhere to the lowest common denominators of the medium, while still offering a minuscule level of entertainement or interest for some of their aspects, mostly because of how bad they are.
3) Bad: almost no pros, hard to watch.
4-5: average shows that are too bad to be considered good and too good to be considered bad. Mostly shows that don't showcase enough quality or have much to offer, but that don't make as many mistakes as the actually bad shows.
4) Mediocre: cons overweight the pros, but still watchable.
5) Fine: cons overweight the pros, but still an enjoyable watch.
6-10: quality shows that I'm glad I watched
6) Good: nice shows for what they do, which is not too much, but still competent in what they set out to do.
7) Very good: great shows that have some major setbacks that don't allow them to shine as much as they could have.
8) Great: shows that do almost everything right, very few issues, if any, sometimes there just isn't enough to them to be considered even better than great, despite in some cases being almost flawless.
9) Amazing: extremely competent shows that tackle interesting themes with great writing and direction.
10) Masterpiece: same as amazing but these shows have also impacted me on a major level, changing some of the ways I think and relate to people and the world.
My scores serve as a remainder to myself and to give people an idea of what my tastes are. While scoring I try to look at shows in an objective way as much as humanly possible, considering everything they might have done right and wrong; that being said it's impossible to be completely objective and I don't claim to be so. Enjoyment is also one of the factors that I consider when evaluating a show, though it's also obviously linked to the quality of the show in terms of writing, direction...
I kept the description of the scores intentionally generic because, after all, numbers alone aren't enough to explain why I like or dislike certain shows. They might have some use for the reason I stated above, but they shouldn't be taken at face value since they are just an artificial way to simplify something that is, at its core, very complex. Everyone gives numbers a meaning of their own, making every scoring system unique and none universal, but in the end that's all they are, numbers, and they can't contain all the thoughts I have on certain shows, not even slightly. So consider my scores just as a rough indication of what I like and if you are in doubt about what I think of certain shows just ask me, that's the best way to go.
I say "shows" for simplicity, I use this scale universally for every medium.
I only add a show to the dropped list if I have watched at least 3 of its episodes.