I've been thinking a lot about this since I watched "The Night Watchman's Journal" (I'm trying to write a fair review of this at the moment but everything that bothers me is a spoiler, and I'm really unsettled about how i feel about plot, acting, cast, music that I'm not sure I can do it)

Do you have dramas that you would like to have given a higher rating but just couldn't bring yourself to do it even though you don't know why?  

Do you have dramas that you wanted to rate lower but even though you don't have a reason you can't do it?  Lets discuss it.  Which dramas niggle at you and worry you even though you gave them a middle of the road rating. I'm so curious about this so would love to hear your thoughts.

no I mean, a drama you put in the middle of the rating road even though in your heart you either loved it more than you rated it or hated it more than you rated it and it bothers you and you don't know why.  Not something you rated half way through
For me that would be drama Big, it was one of the first ones I watched and loved at the time. Looking back now I see it's a so-so drama that could have been a little tighter in writing and some other areas. The ending failed for a lot and it got mixed reviews because of that. The leads needed more closure so it felt open in the final moments.  I guess I love and hate it, and if I rated it again it would be middle of road 5/10 
so for me, the royal gambler/jackpot.  I'm a JKS fan girl, I expected this drama to be bad and i expected him to be 2 dimensional [I'm a fan girl not an idiot]  but i loved it, i loved him in it (aside from the first 4 episodes which are always bad in JKS dramas) but it wasn't bad.  It wasn't two dimensional and now when i look at it i feel like heaps of people decided "JKS is in this I'm going to give it a bad rating"  and it stuck.  this is a drama where i think my second guessing is giving it a lower score than it deserves, Like I should give it 9 because actually it holds up really well against other sageuks and i think i'm rating it lower than I should because i think people will judge me because I'm a JKS fan girl.

empress Ki.  I gave it 7.5.  I think i should have rated it lower.  I don't think it deserved a rating that high but I can't bring myself to lower it

Baek Hee has Returned. This is one of my favourite dramas, why can't i give it a score higher than 7.5.  it's still a good score based on my scale, (like 75% on a physics test - proud) I recommend it to someone every day, one of my three favourite actors is the male lead, but I just can't rate it higher

Blood, best bromance ever.  aside from the last episode it was almost flawless, also Ahn Jae Hyeon does that weird thing with his mouth (like he's chewing gum) when he talks that's totally hot, there's really only one episode that brings the whole thing down and that's the last episode, it deserves more than 7 (even though most people didn't like it) but again, I can't and I don't know why i feel like this drama deserves to be loved more than it is but I can't make myself be the one to do it.

Love Rain.  everyone hated it.  They hated Yoona.  It's the first drama I ever watched and I love JKS because of it.  also when I watched Yoona, i thought "if i met her in person, I'd be confused about my feelings but love her too."  I thought she did such a good job with what she was given I don't get why more people don't love it.  It's the drama that made me go hunting for other dramas.  it's the reason I'm on this site talking to all of you.  why can't I give it more than 6?

the nightwatchman's journal.  This drama makes me want to scream.. I could discuss this more but i'd give it away.  i want to find everyone involved with making this and slap them silly

Scholar who walks the night.  I'd love to give it more than 5.5.  I feel guilty about the score I gave it but whenever i think of it the phrase "just not good enough" pops into my head.
I think I love this thread. Since I'm one of those who constantly changes drama ratings. When I finish something good, I consult my watch list and review my ratings. There are times when I feel like: this drama is so good to have the same rating as another drama I already watched, but I don't feel like giving it a higher rating. It's a dilemma. Hahaha

Okay, so here are my middle-of-the-road dramas:

Empress Ki - I gave it a 10, but I feel like I need to lower my rating.  While watching this drama, I couldn't help but compare this with Queen Seon Deok (which, btw, is my most favorite of all dramas.) Don't get me wrong, I also love EK; it has all the elements I love in a great Saeguk. But I was nearing the end, when a friend dropped a major spoiler on me. And spoilers are a big NO for me; they make me lost interest in a drama. And this is no exception. That's why it took me a month before watching those last five eps. I still loved it though. But, not as much as I would have without the spoiler.  (The comparison with QSD isn't the reason this is on the list. But, it could be a factor, I think.) haha

Descendants of the Sun - I first gave it a 10, because I love SJK and I did enjoy it. But it's one of those dramas that I'm becoming less sure of as the time pass by. It's like I don't know why I enjoyed it in the first place. I changed it to 9, and I'm seeing an 8.5 soon and maybe an 8 later. :D

There are 7 dramas I gave a rating of 9.5: Bad Guys; Cruel City; Falling for Innocence; Iryu Team Medical Dragon; It's Okay, That's Love; Kill Me, Heal Me; and Oh, My Ghostess. 
These are the ones I really really love but couldn't bring myself to give them a 10 or lower than what they have now. I know it's just a 0.5 difference, but it really bothers me. Every time I look at my watch list, I have this urge to change them to 10. But I wouldn't.  I just don't know why. 
But, Oh, My Ghostess is an exception; I had given it a 10 before. But then I realized, there were scenes I didn't really enjoy I skipped a few times. I really enjoyed its entirety though and I don't want it to be given an 8.

Now that I think about it, MDL should create a standardized way of rating dramas. Like, a 10 should be given to dramas with great story, actors, directors, cinematography and all that. That each number should have a description. So that we rate dramas more objectively. And all numbers are used. But, it doesn't really matter. I know we have our own preferences. And we are all here to enjoy dramas which we do. It's just a thought.
Hey @Anniee

I think trying to standardise ratings is really hard, it's so subjective.  I like to look at the stats page as well as the ratings because from that you can see how many people have it on hold or dropped it which puts the rubbish ratings into perspective.  I also look at how people I regularly chat with rate things, because I know their taste (whether I agree or not) to help me decide whether I'll like it or not and read reviews of a couple of regular reviewers I respect.  And also I always consult my drama soulmate ;) 

I like to use all the numbers when I rate too, and sometimes when I look at my list I think that there aren't enough dramas with low ratings, but then I mentally add my "dropped" and "on hold" list and that balances it out. I have a quite harsh rating system, (I've never given a ten and I think it's highly unlikely I ever will) My rating system at the bottom of my profile page if you're interested.

I really find some dramas stay with me even though I thought they were MEH!  The Night Watchman's Journal is the one that inspired this post from a week ago and it's still really playing on my mind.  Why wasn't it great?  It had all the makings of an excellent story.  Did I just not like the lead and I'm tarnishing the whole drama because of it?  Or Scholar Who Walks the Night - why were the last two episodes so bad, why did the director make LJK over act so much, he's a much better actor than the director gave him scope for.  Should I have just rated it higher?  sigh.
@Naksken Just checked your watch list, and you're right: you're rating system is kinda harsh. :D 
But I like it when people maximize the use of the numbers. Which I don't. It's really hard for me to rate a drama. I think I base it on how much I enjoy it. I really want to have a fixed criteria. So, I won't be changing them in the future. Maybe I'll make my own. Hahaha

It's nice that you've found your drama soulmate. Lucky you! I'm wondering if I'll have one.. Haha I can only imagine how easier it would be to decide what drama to watch next since there are thousands to choose from. I don't usually read reviews... spoilers! XD But I like the idea of checking the stats page.