All teams have vibes that are just as contagious as a yawn. Next time you find yourself in a group situation, pay attention to the to the attitudes of those around you. Does the confidence of one person rub off on the group?
Studies and my personal experience at the ropes course working as a facilitator in team building exercises bear this out as truth. When the team is gaining confidence its infectious. Our challenge is to keep that positive attitude growing like a snowball down a hill.