One important element of a successful team is communication. Without effective communication, each team member could have a different perception of her objectives and goals, and therefore not be working in conjunction with her colleagues. Several barriers prevent effective communication.
If team members are physically far apart, such as in different departments or even different cities, then communication can be hindered. Face-to-face communication is a great way of conveying ideas and intents, and not being able to do this quickly and easily can easily form a communication barrier. This can, to some extent, be overcome with video conferencing and other technology.
Language can be a large barrier to effective communication. If the team is made up of people from all over the world, the differences in language can prevent full understanding and effective communication. Cultural barriers also include factors such as not sharing your colleague's sense of humour, religion or beliefs.
Another important element to a successful team besides communication is trust, and if a team member feels that he cannot trust a co-worker, that hampers communication. Information will not be readily shared. Communication should always be open and honest, with any conflict resolved as quickly as possible.
How you perceive others can also present a barrier to good communication, especially if you misread a request. For example, if your boss asks you to carry out a simple task, you could perceive it as her feeling she can only give you simple tasks and does not have faith in your ability. On the other hand, someone else may perceive this as an act of trust, and in giving you this task she knows it will be completed fully.