However, the overachiever is focused solely on the work and on himself, to the detriment of the team. Whenever things appear awry, the overachiever takes over and personally does the work. When the project is going swimmingly, he creates a false sense of urgency. He may, perhaps unconsciously, believe that his way of doing things is best. He may be totally unaware of his behavior.
An overachiever is often seen by anyone who observes the team as an informal leader. Management praises him instead of the team for heroic efforts. After a flurry of production problems, the true effects of the final rush—high staff turnover and morale at an all-time low—become apparent. The hero stays on, waiting for the chance to prove himself once more as the lynchpin.
Why Is an Overachiever a Problem?
Expectations, team growth, mutual trust, group direction, and commitment can be negatively impacted by an overachiever as he sets a pace that few can match, which in turn puts a lot of stress on team members. Managers may judge team members relative to the overachiever, saying “ Joe’s a good coder and puts in his forty-five hours, but Fred is working even more hours and doesn’t waste time playing games at lunch with the others.” Management often favors a person like Fred and overlooks and ignores someone like Joe. As Carly Chynoweth put it so aptly in the The Sunday Times, when there is an overachiever in the mix, the overachiever can turn team into subteams: “You get a sense that there’s an in-crowd who the leader rates and others who are left by the wayside and don’t know why. They will become disengaged and leave.” 
Another problem is that overachievers emphasize short-term results rather than developing their teammates or giving feedback. In believing that they can do the job better than anyone else, they deny others the opportunity to learn and grow. In this way, no individual can improve to become as productive as the overachiever.
Team members might feel that the overachiever doesn't trust them if he routinely pushes them aside when difficult situations arise. Their initiative and responsibility evaporate as they take on the routine, task-focused work. They are intentionally or unintentionally kept in the dark by a hyper-busy overachiever. This sentiment is best summed up by Daniel Goleman from his article, “Leadership That Gets Results,” published in the Harvard Business Review: “People [working for an overachiever often] do not understand where they are going. They’re just following the walk of this turbocharged leader, who doesn’t direct the team but focuses on output. They get annoyed, exhausted, and feel that they need to second-guess what the leader wants because they’re not being told.”