What are the challenges of being a missionary?

Missionaries have to learn how to live in a different culture which includes learning a different language and way of life. Missionaries also are rejected by people for sharing the Gospel and sometimes threated physcially. Some missionaries have been killed for trying to tell people the Gospel.
Many missionaries have to say goodbye to their families and travel thousands of miles to the other side of the globe. Often they won't see their family and friends for many years. But the joys of serving God and seeing people come to know Him personally far outweigh the challenges.