Why do some people drop shows that they've almost finished?

Everything on my dropped list is because the remaining episodes do not have English subtitles.

I've yet to see the last episode of Amour et Patisserie and Soredemo Boku wa Kimi ga Suki.  In other cases the actual company releasing it stopped English subtitles halfway through for Caught In The Heartbeat and Meet in Gourmet Food.

Maybe someday someone finishes those subtitles.

I find often I drop a drama near the end because the leads are together and there no longer is tension or great plot

Personally,I 've dropped some romcom dramas in the last episodes, where unnecessary misunderstandings occur, because I felt too bored to continue. Then, I have dropped 2 series I really loved because I heard the ending was sad and did not want to continue(they are actually in my on hold list  right now, I keep moving them). These I have rated high because I really liked them and I don't think one-two episodes can change that.

 KeenCat:

I find often I drop a drama near the end because the leads are together and there no longer is tension or great plot

Because most K-Dramas tend to have a happy ending, I sometimes find the finales to be underwhelming, and that the penultimate episodes are often the best. But aren't you curious as to how some of them end lol?

 bongbong:

Don't you want to find out how Start Up finishes lol? I haven't watched it yet but it seems to have got lots of mixed reactions.

Nah I actually had barely any interest from the beginning of the show (slice of life dramas usually bore me, also dropped Hospital Playlist at 8 eps with 4 eps left), only watched 'cause of the screenwriter (I prefer their supernatural dramas IHYV & WYWS more) it's one of the most overhyped shows of the year I didn't even care who ends up with who lmao this is the 3rd Kim Seon Ho drama that I found meh besides You Drive Me Crazy and Eulachacha Waikiki 2 (also wanted to drop this one before but I stuck around for Lee Yi Kyung and just because it's "Eulachacha Waikiki") 

 bongbong:

Ah that's a good point, I hadn't thought about that being one of the reasons.  A lack of subtitles probably answer my other question as well, users giving high ratings to shows they've dropped.

Personally for dropped dramas, I think it is okay to rate individual episodes I've seen. I do not think it is okay to give an overall rating to dropped dramas.  That would be like a teacher decided to look at the first 40% of your semester and then give you your final grade for the semester. 

I'm sure others will have differing opinions on this though.

I tend to do this a lot and all I can say is that I either lose interest or am watching something better and forget about it. Dramas tend to make the beginning more exciting to draw in viewers but the end becomes bland or cliche. Sometimes, I'll go back to my dropped list and finish watching the remaining episodes if I have nothing else to watch.