Here is a short snippet on friendship from a Gallup article on Are You Neglecting New Employees:
This is one of the most common ways a vital friendship is formed at work — discovering a coworker with common interests or beliefs. The best workgroups we have studied engage in passionate conversations and e-mail discussions about non-work topics. This helps the group bond and makes it stronger.
Photo Credit: Mr. Pumpkin and Mr. Apple by http://flickr.com/photos/orinrobertjohn/159744546/