Hi Camilla,
I know the drama. It's called
Cheongdamdong Alice (2012)
https://mydramalist.com/5184-cheongdamdong-alice
Han Se Kyung is a young woman with a very positive character. Her motto is "effort will take me as far as I want to go". She wins many designing contests and finally joins a clothing company. But, at work, Han Se Kyung does errands and chores rather than design. Meanwhile, the wife of an upper management employment at the clothing company humiliates Han Se Kyung. The wife is actually a former high school classmate of Han Se Kyung who didn't do better than her in school. This makes Han Se Kyung look back on her life.
I also saw it a long time ago, when it aired, and my only favorite part was when the ML (Park Shi-ho) did a few dancing moves in front of his friend who was also his psychiatrist. But, in my humble opinion, the drama was ruined by the FL (Moon Geung Young).