Do I need to watch the killer's shop list first or can it can stand on its own?
no need, actually the two dramas are not related. (other than they're from the same writer and there are 2 actors starring in both dramas -- but they portray different characters)
So here is my theory about her 1 year break and I am asking you to prove me wrong, bc I really hate it myself,…
In any case, I am OK with a sad ending for Choiseung and Seok-Ryu. I just want a happy ending for Mo-eum, Dan-ho and Yeon-du, hope they become a family soon!
I think WR should move into MR's house now, there is no need to wait for him to get married. I also feel that MR is a bit too pushy in asking him to move in but I understand since she has longed for him for 30 years. Therefore, if WR moves in now, MR can spend more time with WR and bond with him before he gets married. He can always move out again later after he marries SJ.
WC giving SY flowers is so sweet. :) With the possibility of WR moving out of Madangjib, and also the possibility of SJ following him, it's about time for SY to look after her own life now. She knows that WC has feelings for her so it's about time for her to determine if she also reciprocates the feeling.
I think the private detective must have sensed something fishy about JT. But since MR’s lost son is now found,…
Yes, I think the private detective knows that, but he didn't have the heart to bring it up since he saw MR seems happy after HW is found. So he only informed her about the kidnapping.
1 
https://www.instagram.com/reels/C_cxEUPPqk2/
Same with Ara's mom.
WC giving SY flowers is so sweet. :) With the possibility of WR moving out of Madangjib, and also the possibility of SJ following him, it's about time for SY to look after her own life now. She knows that WC has feelings for her so it's about time for her to determine if she also reciprocates the feeling.