Why is it Important that Sending Churches Don't Place Expectations for Quick Results?

Why is it important that sending churches don't place expectations on their missionaries for quick results?

The church needs to understand that when a missionary first goes to the field, most likely his first converts are going to be first generation Christians. First generation Christians bring much joy because it's fresh, it's brand new– but there's a lot of messiness too. They they don't have a heritage of godliness to stand upon. They don't have the shoulders of parents and grandparents and great-grandparents to stand upon, which means it takes a long time. And the the local church back home needs to understand that. I would say missionaries often feel the pressure to send back reports of all of the people on the field that are coming to Christ, and that simply is not so.  There are times when there will be a great revival, but most of the time God does not work through special revivals in the church. Most of the time it's plotting.