The idealistic teammate is important because they help the team remember why they do what they do. The bigger picture can be lost in the moment and the idealist helps to return the team to it. They can seem hopelessly naive at times but they help the team stay on track over the long term. This person is usually the leader because it’s difficult to keep ideals a priority if leadership doesn’t. Teams that lack an idealist often drift from their original purpose and convictions over time.