Although sometimes the "Us vs. Them" approach may get out of the gate a little faster than the "We" approach, over time that process tends to fall flat. Collaboration isn't the easiest thing to do (especially if you have to work with other departments, offices, members, etc.) but, for long-term success, it is the best method.
So, the next time you want to point out how great you are by pointing out how bad "they" are, think of the two bosses above. The short-term good feeling you get from building 'Us' up by pointing out the flaws in others will come back to bite you when you need help from "them" later.