As far as I am concerned, many People tend to work harder than other in several environment such as school and company. They did that, because they think, it is better to perform which outstanding than the other for some reason. One of them is become a bargaining point to the company or organization to hold their position in the organization, and the another reason is to be a person who has capability on the job desk, so they can have priority to be promoted.
Becoming an employee who has a position in the organization is a good think, more than that, the company which always depends on this person that can handle particular job to run the work flow. But, the employee has a consequence to work harder due to the usage of their muscle and brain felt effective by the company. For instance, the graphic designer has to give the product in certain amount of time and must be perfect as buyer order, yet again, it has to be done by itself.
Some companies want to give the reward for the member, like job promotion. They want to encourage other member to work better like the promotion one, the domino effect to the company improvement. This aspect also makes some people work harder to get promoted on their job. For example, some of the marketing team can sell the product much higher than another team, so the team has a good score in the marketing manager, as well as the marketing team leader stands out than other one.
To conclude, it is better to work harder than the others. One of the reasons is to hold their position in the organization, and to be a person that has a priority to be promoted.