I've seen the impacts of changes both large and small, from the introduction of a new computer system to a migration to a new office building.
When you bring in new means of conducting business, new methods of interacting, and new approaches to old problems, you run into some resistence. I can't count all the times I've been told by someone that "that isn't the way we've done it in the past" or "that isn't part of my job."
Change can be good. Change can bring catastrophe. It doesn't hurt to be forewarned, and to read through something like this article on 10 Principles of Change Management
Change does happen all the time. The better you're prepared to deal with it, the less it will harm you.