The fact is, this is true of the Christian life regardless of your calling. Interestingly, though, people who work in ministry have a tendency to be placed on a pedestal, often not of their own doing, and expectations are placed upon them to be more fruitful for the Kingdom than their not-involved-in-ministry Christian neighbors. If people in ministry bear more fruit for the Kingdom, it's often because they are in closer proximity to the front lines, not because they are more righteous or more faithful or more prayerful than their counterparts. The privilege of a missionary is the privilege of every Christ-follower: to follow His leading and allow our character to be transformed in the process.
To be sure, there are unique challenges to the missionary life. Culture shock and language acquisition alone would be enough for some people to call it quits, but add in loneliness, lack of resources, differing cultural values, and spiritual warfare, and it's enough to sound like something only a crazy person would do. All of these challenges, however, offer the opportunity to grow. To grow in faith, obedience, humility, love, service...and the list goes on.
For whatever reason, God has chosen to send us to Africa in order to do some of His work in us. He intends to work through us also, but the work He will do in us is equally important. God is continually crafting and writing our story, and part of that story will be set in Africa, and we will have the joy of letting Him continue His good work while we serve Him there. He's already been hard at work for the past eleven years, molding and shaping and crafting us into more Christ-like people as He's been preparing us to go. But He has much more work to do. And we're glad to let Him do it. The scenery will change, and the circumstances will change, and perhaps the intensity will change too, and His work will continue on. Our prayer is that we will be forever changed because of our time as missionaries in Africa - changed in ways we never could have been had we not been called there. We pray that our hearts will be drawn to him in ways that couldn't be possible had we stayed in the States. We pray that our minds will be renewed in ways that couldn't be feasible if we hadn't followed this call. We pray that our souls will be filled in ways that couldn't be imagined if we'd maintained our status quo.
And this is our prayer for you too: that whatever He's called you to and wherever He's asked you to go (or stay), that you would grow in Him, the author and perfecter of our faith (Hebrews 12:2), as you do the work He's prepared in advance for you to do (Ephesians 2:10).
So when we return from living and serving in Africa, we hope you'll ask about the work we're doing at the hospital, but we also hope that you'll ask about the work the Lord is doing in us. And we'll be able to ask you the same, because He is at work in all of us wherever He's called us to be and however He's asked us to serve Him.
May the Refiner's Fire do its work, on the mission field and off.
"May the God of peace, who through the blood
of the eternal covenant brought back from the dead
our Lord Jesus, that great Shepherd of the sheep,
equip you with everything good for doing his will,
and may He work in us what is pleasing to Him,
through Jesus Christ, to whom be glory for ever and ever.