When a person seeks after something and ends up dissatisfied when he finds it, chances are he was seeking for something else.
For example, if a person seeks for and attains wealth with little satisfaction, he probably wasn't seeking wealth. He was probably pursuing the contentment and happiness promised to him by his perception of wealth and the lifestyle that is promised to come with wealth.
Generally our pursuits are much simpler than the thing we are seeking. When we seek a nice car, we are rather seeking the happiness we feel it will bring us. We perceive a status that comes with the nice car, and want to rise to that status because we feel it would make us feel good about ourselves. It would help us feel content.
I feel Pastors have a similar temptation. Instead of a nice car, they want a nice sized congregation. Instead of a nice paycheck, they want a structure that they feel rises above the rest. If they don't get what they want, they are dissatisfied with their church, or at least the position their church is in. There's a difference between this and being dissapointed because of sin. What I'm talking about is the fact that our specific desires come from a much simpler passion. Do we who are pastors or are seeking to be pastors have our ideal picture of what we want our church to be like, and will be dissatisfied if reality does not match our desire within an unspecified amount of time? Our purpose is the shepherd the flock of God and to help people grow to be God-resemblers and glorifiers. This is all progressive. There is no end to this task. If we have an ideal "spot" or "vision" in which we feel we can be satisfied in reaching, is this no different than the man who fills his storehouses and then tells himself to eat, drink, and be merry? Isn't this a pastors version of materialism? Where are our pursuits? Is our basic pursuit the pleasure of God or the pleasure of ourselves? If we are dissatisfied with anything besides what we envision for our church, chances are our real, basic desires are something unrelated to real ministry. It is not our vision that matters. It is God's.