One of the side effects of being a Mormon missionary is that you meet lots of great people. (Probably because you simply meet lots of people, period.) Some of my best friends today are those I met while serving a mission in Brazil. That includes my mission companions, other missionaries who weren’t my companions, and families living in Minas Gerais. Those friendships and associations are among the best I have.
As I hinted above, meeting lots of people means you meet several negative or unfriendly persons as well. But those relationships fade quickly and the good ones remain.
Missionary work isn’t easy but the benefits are numerous.