Traditional project management is often based on the management style of command-and-control. The project manager decides what is to be done, who will do it when, and then constantly follows up in order to assess progress. Oftentimes the team members are left feeling micromanaged and their morale suffers.
Team dynamics within Agile are dramatically different. Instead of being micromanaged the team is allowed to think for themselves, they are allowed to solve their own problems, and make their own design decisions. In addition they are not assigned work; they mutually agree with the customer on what they will build iteration by iteration and then individually choose on a daily basis what to work on. By allowing team members to sign-up for their own work they tend to be more motivated to succeed.