Succeeding at work is often way more nebulous than succeeding in school. School is entirely based on tests and homework with transparent grading systems and syllabi.

Work is so much more relationship-based. It's not just about doing what your told, but also about collaborating and communicating and leveraging a network, mentoring peers, and generally getting things done for which there is no clear path.

I always felt "leadership" was a meaningless buzzword in school (especially since it had no impact on grades), but now that I'm working I can see it's a real valuable skill and essential to motivating others to do good work.