2.) Vincenzo (20) - Vincenzo (the character) is so fun and the villains are great (idiotically underestimating vincenzo aside)
3.) While You Were Sleeping (32) - It's got everything. And I'm quite surprised to find that this one was actually this long. I don't remember it feeling like it.
5. Welcome to Waikiki (20) - The characters were so goofy and funny, I just wanted to see what more chaos they had in store and the final pairings (even though pairings were done I wanted to make sure they didn't change or something).
8. Five Children - 54 episodes, 1 hour 10 min each. Multiple couples with the main couple being a widower with two young children and a divorcee with three. Very likeable characters (well, mostly).
Not to be too technical, but I'm assuming the poster is referring to the common 16 hour long episodes, and one of the common alternate formats is 32 half-hour episodes, so technically While You Were Sleeping is the average 16 episode length.
8. Alchemy of Souls part 1 and part 2 (30 - Netflix just divided it into 2 parts) - despite the flaws of the plot itself, the cinematography and acting is really good. Besides that, its multi genre that I rarely see in kdrama.
9. Pasta (2010) - 20 episodes - I honestly really enjoyed it. I love secret relationships and theirs was quite entertaining to watch (even if the ML was a hypocrite by being in one). They are also a very cute and loving couple though the ML could be a bit harsh at times. The supporting cast was enjoyable too, my favorite being the co-worker who actually found out about the relationship. If you want to feel hungry, then watch this. I know I was. 🤤
3. A romance of the little forest - not sure if the secondary couple really did get more screen time than the main but it sure did feel like it as a viewer