This drama was somewhat enjoyable, but that enjoyment is marred by almost unforgivable flaws, as follows:

1. The FL's acting just grated on my nerves. I don't understand why she had to overact and shout so loudly and gesticulate so violently all the time. I guess that was her version of "funny and dorky," but it just felt horribly irritating, especially in the first few episodes. She just was too over-the-top. I think overacting is an understatement.
2. She actually looked better with her frizzy hair and freckles than when she was made over (the makeover made her look noona-ish) and yet the drama implied she was somehow not being her best self in the earlier parts just because she wasn't into makeup and fashion. Not all girls are girly in that way, and it's fine. It's fine too that she decided to put on makeup later on, but I didn't like the way she suddenly became quieter and more ladylike. It seemed too unnatural and made me feel even more emotionally distant from her.
3. There are too many frustrating communication problems. I couldn't count how many times the characters (especially the horrible friend) had something very important to say and were like, oh, I shouldn't tell him/her now because she's not in the best of moods. If something is that important and you know your not telling the truth will just end up hurting people, you need to tell the truth ASAP. Maybe try to talk to them so their mood shifts and they calm down, and then tell them. You don't drag it on for days and weeks. I get though that she may have only been using that as an excuse to not tell him the truth. Pretty stupid, considering she must have known she couldn't hide that truth forever.
4. The second male lead is just too charming, fun, flamboyant and cute that he easily overshadows the main lead, whose character is stiff, boring and unlikable. IMO, this is the main flaw. The kdrama romcom experience is so much better when you actually fall in love with the main lead for the space of 16 episodes. Sadly, that's difficult to accomplish here because of the way the character was written. Or is it PSJ? I really enjoyed him in Fight My Way, but I think that was the only drama of his I liked. In Hwarang, he was, IMO, again overshadowed by Hyung Sik. In Hwarang too, and in his other roles, his characters tend to be a bit boring and a bit stiff. Just IMO. But nowhere is that emphasized more than in this drama. The second male lead definitely stole this show. He had a funny persona but you could tell, in certain moments, that he had great sensitivity and depth. The actor played the character really well. You can see the fleeting moments of sadness in his eyes when no one is looking. His character was just so much more interesting.
5. My main beef: how the male lead was obviously obsessed with his childhood friend, and the drama seems to think it's cute. Like how many grown-ass adults do you know who are still pining over their childhood crushes? And let's face it. That was all it was -- puppy love/a baby crush. Everyone had a childhood crush, but what healthy person actually clings to that without developing other healthy relationships as they go through life? Everyone outgrows those crushes. Yes, you may eventually reconnect and might fall in love, but to draw a straight line from what you felt when you were virtually a baby to what you feel as a grown adult man is just not right. And to actually keep mementoes of your childhood crush in a glass case? That is almost creepy IMO. Like how can that be cute??? And it all points back to that Korean obsession with children falling in love, which oftentimes has an incestuous twist. They not only strongly correlate it with being "destined to be together" but they also obviously find it super cute. Anyway, why can't two strangers meet, jive and fall in love, without ever having met ever in childhood? In kdrama that is not allowed. If you didn't meet as children or babies, that means you were never meant for each other LOL. Anyway, this obsession with his past would've been something I would forgive easily if the main lead was more likable. It just annoyed me, but could have been easily forgivable in the context of kdramaland. It just was more annoying here because of the way the main character was written.