That part when she cried... : (she was happy with just a little action, like her brother giving her the water filter.

Characters are quite likeable. Though I get frustrated at the part where MC kept denying ML's low key courting at first. Though I get it. MC is inlove with ML long before ML realizes his feeling, which makes things seems like its too good to be true and just when MC decided to give up on her feelings with ML.

MC is cool indifferent type but soft hearted and sensitive. I just felt suffocation when she was still in the Mu's Home. It felt so sad that she was treated like that.

ML is just soo sweet and matching with the cool rich bad boy image can just make my heart.

The grandma and ML's mom, have a feeling that there was something different between the MC and ML when they switch. So when they finally met each counterpart, they were able to recognize them and accept them as their own grandson/daughter.

Mu Dad and Fake Daughter's Fiance are just terrible scum men.

MC's brother, I just felt sad for him. He's just 16-17, and he had to be stuck between the guilt for how the family decided to treat the MC, or the rest of the Family's collective decision to lie. He flew abroad because he didnt want to be burden with the lie. He tried, in his own awkward way, to get along and care for MC (i mean shes his twin). But he can only do so much. It was funny how he seems like very cool, but it was not known to many how he cant do alot of things that MC CAN do and he felt depressed.

I also felt sad about the friend of the MC's brother. His mother seems to be suffering from Munchausen by proxy and he s having a really hard time. His bro who has an originally cheerful personality just snaps and commited suicide.

I don't know if the translator used MTL, or didn't finish the novel before translating the summary, but in the story the FL basically said "yes" to dating the ML and the ML actually says the "Be my girlfriend, although you are from a small family" in a teasing and joking way - because the FL already kinda? Promised to date the ML before that. (So the ML actually isnt such a big dick)

She's not good at Go (A chess of some kind) so she thinks carefully about whether joining the competition would let her earn money or lose money (the prize money earned from the competition and the money it cost to take classes) . Not related, but she lost to some guy at Go whose name I only remember as laughing Onii-san since his name kinda sounds like a laugh and the FL nicknamed him that too.

I loved how both MC's grandma & ML's mom recognized them right away through their little habits like touching your nose when you're embarrassed or addiction to garlic. How realistic it was for them to see the difference when their 7 year old would change personality and finally, how nice it was for both of them to accept the other kid as theirs too. Many other author would've taken that as an opportunity to create unnecessary angst when really, it was the best opportunity for a heart warming moment.

Second favorite, ML's realization of his romantic feelings and decision to pursue MC when he realizes it's not mutual (really it was but she gave up on him because this dumb*ss was being way too dense for way too long and kept saying how there's no way for anything between them). I was afraid he'd give up and there'd be never ending misunderstanding, angst and jealousy inducing situations to finally pull them together. Very happy again that the author didn't take the easy/stereotypical route and instead had her ML mature so much, I'm so proud of him.

Finally, as kind of a sidenote, I don't now if the author has personal experience with very bad period cramps and endometriosis but I appreciated the way it was talked about. The subject of periods is rarely seen apart from in some rare cases in a comical way and well I think that for every women who suffer a lot for a week every month, it's nice to have a realistic representation.

I feel so bad to see the ML got praised for all the efforts that MC did when she is in the ML body. Like one of the reviewer said, it feels like "wife is seen but not heard". I hope whenever ML is in MC body, he doesn't only help to endure pain, but also help MC to gain glory.

it is also disappointing to see the Mu family attitude in handling the problem. They can handle it better, but they don't. I can't bring myself to hate the female main villain because she is also the victim of what happens in the past.

the dad. Even the adopted sister evoked pity from me.

I especially loved the fiance's family's response to finding out about the identities of the daughters. They were most upset at the family for not trusting enough in their friendship that they felt the need to lie about it and mistreat their real daughter. They broke the ties because they realized the dad was just a bad person, not because of financial/political reasons.