Success of colleagues can motivate and demotivate other people at work. It depends on the employees in question and the working environment.
The colleague's success is more likely to be motivating for staff if it’s perceived as fair, and something that other staff can potentially achieve with the right talent and hard work. It can help to foster a positive competitive spirit of improvement amongst staff, which can be good for creativity and productivity.
However, if the success is seen by other staff as the result of unfairness, cheating, favouritism or just pure luck, it’s more likely to be a demotivator. This is because staff will conclude that they have little control over their own chances of success.
As with stress and fear, staff may be motivated to a point, but it may also be damaging.