Let me start:

The extra scene in episode 13 where they were in the car and Duan Jiaxu bought Zhi strawberries. Right after Jiaxu ate the strawberry from Zhi's hand they were like laughing because  of the song that was suddenly played in the car radio (OST Be Your Light), the faint smiles and how they look at rach other ㅠㅠ I really felt through the screen, it feels so real. I had butterflies in my stomach. I really think it's one of the underrated scenes in the show that really shows us their chemistry. I feel like an outsider watching their moment?

When  Sang Zhi thought she was setting up the beach proposal for her friend. The whole scene took my breath away and I even shed a few tears. Top-notch acting from both leads and the background song was so touching

That is a difficult question because there are so many lovely scenes. 

I tried to hint to them in my entries for Episode Guide, and it was sometimes difficult to hint without telling totally, so episode 13 which is a festival of seductive "warfare" (there are other ones in subsequent episodes) got a full breakdown from me, which is best read after having seen the episode so as not to be spoilerish...  My entries  in the first episodes were just to remind that the whole drama used the "end puzzle" device as a sort of game to enhance the pleasure of attentive audience. Later, some entries are more to remind audience of highlights and important moments. I selected as titles for several episodes a sentence from dialogue.  Like this one :

EP15  "After all, you're not my girlfriend yet"

The episode is all in small, physical and mental touches, holding onto arms, supporting in firm and steady grasp, be it the girl or her drink, and playing on warm and cold temperature, of Jiaxu's hand too.  They were already speaking together in unison. The build up to establishing relation was progressive and inevitable. Jiaxu was now in full bullet train flirting mode, messing with Zhi's mind to take her to his place, and make his intentions crystal clear in candlelight at her 19th birthday. She was getting used to him,  and accepted that he woo her until she could make sure if she liked him!

--- Puzzle : Jiaxu was learning to bake, with a professional baker, and had to try several times before he could bake the non dairy lemon tart Zhi would prefer.  Do you remember why he did so, and where this fit into the episode ?

**** In the previous episode, one moment  had me pause to understand who/what  Jiaxu meant, when he asked "Shenlan" to connect him to "Qianfei" just after they had flown back from Nanwu, and Jiaxu was thinking while driving his car in Yihe.  How was he phoning, did he have a secretary called Shenlan, and why was it so urgent that he called his friend Qianfei at whose wedding party he had been the day before?

EP14 "When do you plan to tell her ?"

 This episode had funny moments including cute mirror like behavior :    

Sang Zhi was holding back, disbelieving that Jiaxu could have feelings for her; luckily she had supportive roommates who gave her funny advise on how to "strike first" at the "enemy" :))  Jiaxu had been worried at her coldness on the way back from Nanwu, but asked likewise Qianfei for advise about how to pursue "his girl".      -  He asked her out to early dinner, but  nothing went as expected : he showed up accompanied, and the ensuing embarrassment took a literal toll on Zhi's face !      

----"Half-baked" ? Puzzle piece at the end : Jiaxu was in the office and asked for a favor from his superior to dispel a misunderstanding and save his face... (This piece is easy to place in the episode)      

It was endearing and funny to see how the actress portrayed the sudden blooming in beauty of the girl in love, with glossy hair and tasty light clothes coordinated to her white and black dress sandals with modest heels. Chen Zheyuan and his outfits and glasses were also like a top model there, with his denim shirt mirroring the color of the azure skies.      

And did you notice his wolfish smile and drumming fingers on the wheel before Jiaxu asked the vocal assistant in his electric car to connect him to Qianfei?  That was a neat product placement of the Shenlan SLO3 EV competitor of the Tesla car, launched on 26 July 2022 by Changan Automobile, based in Chongqing.  Coincidentally, ShenLan is also a popular pairing (ship) of characters in the Genshin Impact  open-world action RPG launched by MiHoYo, Shanghai Miha Touring Film Technology Co., Ltd. on September 28, 2020.

I wondered if the scriptwriter had done it on purpose, that coincidence of product placement for the latest car and possibly for the e-game, since Jiaxu is working in e-game design?  But I think not. Unless the scriptwriter is a die-hard gamer and reader of related fanfic, that may not even be available in China since most of that is published on banned sites such as Ao3.  Myself, I am aware of the ShenLan ship because I am curious about a lot of stuff, including  fannish trends, but only from a once-removed distance, since I am not a gamer myself, only living with some who are. I am from a generation which used to read differently, although it's been a while since I embraced the new e-reading trends and followed different heroes after the Condor ones, all the way to funnily genderfluid Xie Lian and singing along with Luo Tianyi (btw, let's celebrate this favorite alien and angel of music's official birthday tomorrow July 12? Shall we have non dairy lemon tarts for the occasion?)

--- So let's select a favorite there ?

The scene to the end of Ep14 where he found her outside the pharmacy, hiding her face wrapped up in her dark blue sweater, half niqab style, showing only the expressive eyes looking disappointed, nervous, self-conscious and smiling mischievously. --- She suddenly looked like an oriental princess of fairy tales only missing the jewels dangling to complement the glint in her eyes, and when he dragged her away holding both her hands in one of his, and she jokingly protested that he was leading her as if she was a dog, I was having pictures in my head, superimposed, of a sexy muscular barbarian from torrid fantasy, dragging his favorite and willing slave to his tent  !!  It was both goofy, endearing, and hot. ?? ? Completely turning on its head the "overbearing CEO" and "meek submissive love interest" archetype, in a suggestive but funny symbolic way.  

But Jiaxu was always ever respectful of her decisions as he stated in his car : "What other girls have, our Zhi must have." So the goofy scene, of course, just  was to help her keep from scratching at her allergic rash, and bring her safely home to her dorm.  Sweet. She did not fight his sort of manacling because she really had trouble keeping her nails from making the rash worse, before the medicine worked enough that she could take off the sweater and talk to her roomies before going to sleep. 

 It reminded me of similar itchy moments to live through (moskitos, allergies, chickenpox before vaccines were available) so I thought it was a very realistic touch, on top of the symbolic itchiness feel of sweetness ?.  

I swear I could name lots of favorite scenes in the drama but my top 3 are as follows:

1. The first time Duan Jiaxu thought of Sang Zhi when Qian Fei asked him if there’s someone who somehow caught his interest. I keep repeating the part where he flicked the bear post-it coz at that moment, awareness dawns on him about his developing feelings for Sang Zhi. It’s giving me all kinds of feels, I keep hugging my pillow on this one.

2. The airport scene where he realized Sang Zhi might have mistakenly thought he had a girlfriend before. The cute, little smiles he was trying so hard to tamp down are so endearing, you can see hearts in my eyes on that scene. I repeat that scene over and over again and I would squeal like a fool every time. Hahaha!

3. The proposal scene. The words Duan Jiaxu said to Sang Zhi moved me to tears because he was laying all his heart down in that moment. Six words. Only one person in a lifetime. OMG! He was crying, she was crying and I was crying, too.