Culture shock

The feeling of disorientation experienced by someone when they are suddenly subjected to an unfamiliar culture, way of life, or set of attitudes. (Lexico)

The nervous or confused feeling that people sometimes get when they arrive in a place that has a very different culture from their own (Macmillan Dictionary)

The feeling of being confused and worried that somebody may get when they visit another country or experience a different way of life or set of attitudes because the experience is so different from what they are used to.  (Oxford Learner’s Dictionary)

A sense of confusion and uncertainty sometimes with feelings of anxiety that may affect people exposed to an alien culture or environment without adequate preparation. (Merriam-Webster Dictionary)

To summarize: The feeling of confusion, disorientation, nervous feeling, being worried, a sense of uncertainty, sometimes with feelings of anxiety when suddenly experiencing an unfamiliar culture, way of life, or set of attitudes that are very different from our own, without adequate preparation. 

Sure, not everyone experiences all the above-mentioned symptoms, especially when we are exposed to a new culture for a short time only. And not at the same time, that would make anyone's stay in a new place quite miserable. Also, it would put us off travelling for a life.

It is said that culture shock is good for us. Experiencing different cultures widens our horizons and makes us more tolerant. There are more ways of living and doing things, one is not better than the other.

The problem comes when we are not prepared for it, when we start our journey with stereotypes in our heads, when we continuously compare a new culture with our own. The last two would prevent us from enjoying our stay.  

On the other hand, when it comes to preparation, it is very unlikely that we can prepare for everything. Even if you read a lot, watch documentaries and movies about the new place where you are heading, you will encounter unexpected things. Also, there is a big difference between going on holiday and moving to a new country. The latter has more stages and deserves a new post.