Shopping can be quite a chore and require many hours of time. In certain areas the climate can be stressful. Interactions with government officials can be exasperating and time-consuming. There can be interminable delays in securing needed goods or services. Satan is active and is opposing attempts to win converts and plant churches.
Progress can be agonizingly slow.
Results may be very meager even after years of work. In interceding for missionaries don't forget to pray for this combination. General and non-specific prayers are not sufficient. Our prayers must be informed and Spirit-directed.