Develop a closed-door mentality. Remember, Albania, Pakistan, Tibet North Korea all turn down visas from time to time. Develop a 'national church can do it' attitude. Never investigate the percentage of the population they constitute, or the severe limitations of their resources. All fair-minded Christians will applaud your concerns about the 'unsaved right here in our own country'.
Missions begins at home - make sure it finishes there too.
Of course, ignore the examples of Peter, Moses, etc. Always look at those involved in mission as super-spiritual people with extraordinary gifts and saintly characters. This will heighten your sense of inadequacy and remove any guilt complex about trying to be like them. That way you will be back soon and can say you tried. Never sing the hymn 'Onward Christian Soldiers'.