The only reason I rated this show so highly was because of Bin Bin.
He's a terrific actor in each and every show I've seen him in, and this is no exception.
He carried this for me.

Characters:

ML is a very smart and capable IT programmer/designer. His ambition is to help build satellites/satellite navigation systems.
FL is the rich grandchild of a conglomerate owner with no great ambition in life.

Plot:

ML and FL are old high school classmates. She chased him but he seemingly turned her down.
They part on bad terms.
The show opens when they meet again at a subsidiary of Grandpa's conglomerate.
He's the leader of a tech team whose talents have been overlooked in favor of those with better connections.
She joins the company as a deputy team leader after betting with her grandpa that she can build up the failing subsidiary within a year before HQ decides to close it permanently. In exchange for doing so, Grandpa will stop pestering her to get married.

If I had to encapsulate the story in several words: The struggles of succeeding in business and achieving our dreams against a backdrop of workplace politics, financial struggles, and family struggles. And finding the right person, and sticking with them, despite all odds.

The relationship between the ml and fl is not antagonistic exactly, but they do push and pull each other in the directions they each want to other to go. Each somewhat manipulates the other in order to get their desired results.

The ML cares deeply for the FL and works extremely hard to protect her. Aside from one incident when things spun beyond his control, he never does anything throughout the entire show to harm her or hurt her feelings. He's too selfless sometimes. I only wish he'd used his words. Because while actions 'should' or might speak louder than words, in this case, our FL was just too dense to recognize what was happening, and this ended up hurting the ML unnecessarily.

The FL is innately kind. She'll go to bat for those she cares about. And she will not silently swallow or watch injustice. She's a fighter and l love that about her. She's also very witty and sarcastic, the queen of one-liners. She made me LOL multiple times.
My one gripe with her, and this is a big gripe which continues through a large part of the developing story, is how she treats the ML.
While she's kind to everyone, as I said earlier, with him she isn't. Or, at least, not to his face. She blows hot and cold so often and suddenly, that it's impossible for our poor ML to know if he's coming or going. Through no fault of his own, he's forced to put up with her drastically changing moods and her inexplicable temper, all the while being left in suspense about how she truly feels about him. Another thing she's the queen of is mixed messages. That's cruel and childish of her. A grown woman of 26 should behave better.

My favorite part of the show began at approximately episode 20. That's when things really started getting good.
However, the last three episodes introduced a new conflict which the characters handled in a way I didn't like. As always, it was the FL who annoyed me the most with her response. Although for once, the ML wasn't 100% blameless here. Since the two were already a couple at that point, he could've handled things better. I still appreciated his responses though, and admire him for what he did.

Ultimately all conflicts are resolved and we are shown everyone's happily ever after.
The ending was very sweet.

Music and Cinimetogrophy:
Mediocre

Acting:
ML= terrific
FL= fine
Side characters= solid

Rewatch value:
6.5 to 7