Notice what Herbert Kane said about the missionary. Drop your ideas that he or she is some sort of super saint.

There were, and are, spiritual giants among them, but the average missionary is a man of like passions with ourselves (Ja 5:17). He is fashioned from the same clay and he, like us, has the treasure of the gospel in an earthen vessel (2 Co 4:7).

He may have a heart of gold, but he has feet of clay. When he lets his hair down he looks very much like the rest of us. He is basically a spiritual man, but he has his full share of idiosyncrasies. He has his headaches and his hang-ups, his blind spots and his pet peeves, his prejudices and his passions. He even has his doubts and fears. Touch him and he’s touchy. Cross him and he gets cross.

There are limits to his endurance. He has cracked up physically, mentally, morally, and spiritually and has had to come home to an unsympathetic constituency devoid of understanding. He has been known to fall into sin, including adultery, homosexuality, and suicide. Not all missionaries are happily married; they have domestic problems. Not all MKs turn out well. Some of them go astray. Some resent the fact that their parents are missionaries. Some become rebellious and join the hippies. A few have been known to end up as agnostics or alcoholics.

The missionary, like the apostle Paul, lives by the grace of God (1 Co 15:10) and cherishes the hope that by a process of divine alchemy the infirmities of his flesh will become an occasion for the manifestation of the power of Christ (2 Co 12:9). In and of himself he can do nothing (Jn 15:5). With and through Christ he can do all things (Ph 4:13). Others may have illusions about the missionary; he has none about himself.

 J. Herbert Kane, Understanding Christian Missions