I need a drama that makes you motivated to work/study and do a good job. So I guess something where the lead is climbing up the career ladder or peforming well on his/her studies and working hard. 

Any suggestions?

incomplete life (misaeng) the only one that comes to mind
Bachelor's Vegetable Store.  Man, that guy maintains his cheer and perseveres with his dream no matter what ridiculous plots/people block his path 
I second misaeng. by the end of it, I found it to be a highly inspirational/uplifting story---comforting, even.

candy house comes to mind as well. it's more of a reflective, very reality-based slice-of-life (altho it is not without humor), but it made me re-evaluate myself & my choices. it made me want to do better & be a better person---to do good & well & be happy, but not forget what's important---if that counts for anything.
Cheese in the Trap was pretty good for that (Seol, and to some extent Jung, and even In Ho) for the school part, but then the end kind of negates it all, so...maybe not :)

Dal Ja's Spring did the career and work/life balance thing pretty well.

Good Doctor follows someone as he becomes a doctor against the odds (and also features other doctors in training as they achieve their own goals) and Gourmet is about chefs and finding what you're meant to do in life.

Page Turner hits some of those same themes, with high school kids and music, if that appeals.  Taereung National Village is young adults at Olympic training camp, so not quite studying or a typical career, but working hard all the same (and finding loooove, of course.  It is a kdrama, after all).

Also Baker King, I guess.  If you want the most melodramatic version of someone climbing a sort of career ladder, haha.

That's what I can think of going through my list.  Hope that's helpful, or at least amusing ;)
I found Dragon Zakura very uplifting the first time I watched it. The kids in the story sought to enter the prestigious Tokyo University--an impossible feat, according to almost everybody, because they're from "bad" school and not deemed intelligent enough--and in the process found confidence in themselves and the courage to dream beyond what society thinks they're capable of doing.
although i haven't watched it, recommendation i read said that Juhan Shittain hits motivation at work big time

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If you don't mind C-dramas Boss & Me has very career-driven female AND male main characters. It's a workplace romance that balances the romance and career well.
maybe you will be interested in this http://mydramalist.com/18517-hope-kitai-zero-no-shinnyu-shain
You should watch 
Dragon Zakura (study)
Good Luck (work)
Attention Please (work)
Doctors (work)

Itaewon Class --> we see how the main lead never gives up et tries his best to upgrade his work to the highest level which I found motivating plus the plot of the story is great :) Definitely should try. (there's kind of everything in it : romance, drama, action, revenge...)

Weightlifiting Fairy Kim Bok Joo --> it's not the main thing in this drama but we get to see the evolution of the career of a young woman (romance, drama)

Eulachacha Waikiki --> the characters in this drama would always fall down but would always also get up and fight for their dreams. It's a very fun and light drama who gives you positive vibes, recommend it a LOT! (fun, ROMCOM)

1. Hit The Top / The Best Hit 
    FL is in college and studying to become a lawyer~


2. Just Between Lovers 
    FL works hard after being in a accident when she was younger that inspired her to join a certain field of work


3. Touch your Heart 
    FL is an actor studying/ working at a law firm so she can get her next role as a lawyer


4. Basically Most Doctor Dramas  eheh~


Hope you find one you like!