I've seen quite a few people bashing this drama but I personally really enjoyed it.
From the production all the way to the actors and storyline this drama is everything I have been searching for.
I personally am a sucker for office-style romantic comedies and I was looking for one where the FL is the CEO as opposed to the ML being the CEO and this drama was suggested to me multiple times. It took me some time to "get into the mood" for it, but once I did I got to enjoy three days' worth of laughter, tears and butterflies!

If you're anything like me - enjoy cheesy rom-coms, amazing friendship dynamics, character development, internal conflicts and learning something new, then I suggest giving Start-Up a go.
I really like dramas that have educational bits and bobs in them and similarly to Suspicious Partner, this drama had small explainers throughout on business, investing and start-up terminology which I found very educational. In addition, if you have no idea how start-ups work, then this looks like a fun introduction. Also, I really enjoyed how each episode had a start-up related theme, which also tied in with the whole storyline of the series (character development, relationships, what events may take place etc.).
I also wanted to give a separate shout-out to the director and production team. I managed to cry nearly in every episode including the first. I mean, I have never had such a strong emotional connection to a drama - crying on episode one. But I think the storyline was so greatly developed and the actors were able to portray that storyline so well that viewers could emotionally connect with them, feel what the characters felt and let their emotions go wild!

Honestly, this drama was a great journey and I would definitely watch it again :)

Okay, SPOILER-FREE review over, let's get into the good stuff!

This drama was my introduction to the wonderful Bae Su-zy who is considered to be Korea's Sweatheart and oh boy do I see why! She embraced her character so well and was able to portray an amazing Seo Dal-Mi and one I could relate to. A girl in her mid-20's who doesn't really know what she wants to do and is stuck fantasizing about a boy she wrote letters to 15 years ago who she never met turns into an astounding woman, who is strong, confident and inspirational. The amount of character development she alone goes through from doing things just to win in a battle against her sister to actually having a goal that is for the greater good and not for a petty vendetta.
I also really liked that this drama highlighted the fact that you do not need to have a university degree to succeed in life, however, if you do not, people will judge you and think you are "stupid" or "not worth it". Higher education is ridiculously expensive and not everyone can afford it - that's why start-ups and small businesses exist - to give people a chance to succeed.

Nam Joo-Hyuk portrayed a great ML. Nam Do-San was just perfect. I really enjoyed that for the first time in a long time we had a ML in a drama who was sincerely interested in the FL and did not try to hide it (unlike our second ML Mr. Han Ji-Pyeong). Yes, he was a little bit of a geek but his geekiness made him so innocent and pure that he brought me pure joy. You could see his actions were reflecting his good intentions and even though they might not have been the right path at times, he was such a pure soul I wanted to protect at all costs.
It became quite clear from the very beginning that Dal-Mi and Do-San would end up together at the end and honestly I did not mind that. I oftentimes hate love triangles, just because the second ML usually gets dumped, left behind all by themselves (which was sort of the case with this drama), but Ji-Pyeong annoyed me a little so I was a hardcore Dal-Mi x Do-San shipper.

Ji-Pyeong was portrayed by Kim Seon-Ho who I think did a great job of playing a lost and lovestruck man who doesn't really know what family means or how to express his emotions. By the choice of my words, it becomes quite clear that I was not the biggest Ji-Pyeong fan, but I can excuse a big part of his actions on the fact that he grew up in an orphanage and never knew what family meant.
I mean, this guy lived with Dal-Mi's grandmother for like a year, made a ton of money, left for Seoul and just disappeared? Who does that? Personally, it feels like pure disrespect to the person who took you in and I was very happy to see him integrate into Dal-Mi's family later on in the series (I was also really rooting for him to end up with Dal-Mi's older sister In-Jae just because it made more sense for him to end up with her - they were both older, ambitious, successful... and well, lonely - match made in heaven if you ask me! And I am really hoping they ended up together once the drama ended :))
Another thing that really bugged me about Ji-Pyeong was his lack of balls. Let me explain. Ji-Pyeong was way older than Dal-Mi and Do-San. While Do-San was in San Francisco for three years, Ji-Pyeong did not get the courage to just ask Dal-Mi out, I mean he made his feelings clear, she shot him down once, and he just sat back and watched her hoping Do-San will never return back to Korea. Again, who does that? This man had so many chances to just get the girl of his dreams and he lost them all. Then, when he saw that he was going to lose to Do-San when he came back from SF he decided to play it dirty by lying that he was dating Dal-Mi. God this man bugs me. He did call her telling her he regretted his actions straight away but Jesus I was ready to punch him at times.
Because of his actions though, we can see he is kind. And I am happy to see him finally let go by the end of the series. It's refreshing and shows growth and I am really hoping he finds his person later on.

Now, I wanted to give a special shout out to Seo In-Jae, Dal-Mi's older sister portrayed by Kang Han-na. Honestly, I first couldn't understand how a child could just so coldly turn their back on their own father, who only wanted the best for them. I mean she was a stone-cold **** and I hated her guts. Even after when Dal-Mi was let go from SamSang Tech when it was acquired by 2STO and you could see In-Jae felt bad for her sister she did not offer any help. Just advice which was delivered in such a harsh manner, maybe it would have been best to say nothing at all?
I have a lot of pride, so if I were in Dal-Mi's situation would I have been able to go for a job interview at my sister's company, who was hiring, knew I was in trouble and did not offer help? Probably not. But I guess this is what the drama tried to show us - that maybe sometimes it's best to step down that pride pedestal and choose your battles wisely. If Dal-Mi would have never joined In-Jae's company, they would have never made up. Granted In-Jae did go through quite a lot but I really wish we saw her character development earlier on in the drama and not just in the last few episodes.

I also wanted to mention the friendship dynamics represented in this drama because they were so good. I never had such a close group of friends like Do-San had and I would kill to have even half of what he has in the drama. Their friendship is so strong and you can see them supporting each other no matter what. Inside jokes and the way they act with one another were also so realistic, it seemed like the actors themselves had fun shooting their friendship scenes.

And of course family! The drama is big on family and children-parent relationships.
First, we have Dal-Mi's family which fell apart when she was in her early teens. She and her sister stopped talking pretty soon, her mum was not present and her father passed away early on so she was brought up by her grandmother. We can see how much admiration Dal-Mi has for her grandmother, how much she cherishes her and cares for her. We can see how her grandmother is trying to mend and bring their family back together by accepting back Dal-Mi's mother who left Dal-Mi's father in one of the worst ways possible. I think this drama did a great job at representing women as the head of the family, which is so important (even when it came to Do-San's family you could see his father "had the upper hand" but his mother controlled it).

Then, we have Ji-Pyeong, an orphan who doesn't know what family is but so desperately longs for it and loses it only to regain it again. I think his storyline was pretty great and contrasted with Dal-Mi's perfectly.

And finally, we have Do-San, an only child - the son, who made it his life's goal to please and make his father proud and kept failing. His failures built up this fear inside of him which stopped him from telling his parents the truth. I think the part where Do-San tells his father that they should no longer strive to be each others' pride was a key development in their relationship. I also really enjoyed all the parts where Do-San asked his parents for dating advice, which, if I am not mistaken, came only after the pride conversation he had with his dad.