G. Mark’s Answer
A complaint I get from many new employees is that they performed well in school, they were obviously talented enough to get the job, they do their assignments completely, but they aren't making as much progress as they think they should. The problem is that they are performing their job exactly as they performed in their college days. In college, you are usually an individual contributor being judged on personal performance of assigned tasks.
In a job, you are likely to be part of a team. And to maximize the effectiveness of the team, you need to leverage the abilities and attention of other team members. You need to sell your ideas, interact with and communicate with others. Eventually you'll need to share your knowledge with new employees so that you can move to other assignments. You need to explain new ideas to other people. Whereas in college, you were learning what other smart people have already discovered and other students were reading or watching, in work your job is not to reiterate what is already known, but to share any insights or innovations or problem solutions with others that you personally have generated.
So while others may have shared the specific challenges of their job, the thing that tends to differentiate a job from training for a job is the practical needs of business. And business differentiates itself from competition by taking what is already known, building on it, and sharing this intellectual capital via communication.