Why should you anticipate culture shock?
If you are an international instructor teaching in the U.S., it is likely that you have excellent English language skills and function effectively in any number of professional environments in the U.S. You may not expect teaching to be any different. However, teaching involves entirely different kinds of interactions than other professional and social contexts. It makes different linguistic demands and requires an unusually high level of cultural nuance. Many international instructors find that in order to teach effectively in the U.S., they must adjust much more to their students than they ever anticipated.
Similarly, if you are a U.S. instructor teaching students from a culture other than your own (whether at home or abroad), you may assume that the pedagogical approaches that have always worked for you will be equally applicable in your new teaching context. You may also assume that since your students chose to study at a U.S. institution, it is their job to adapt and not yours. However, teaching approaches that worked in one cultural context may not necessarily work in another, and instructors who assume the transition will be easy may be in for a shock.