I’m looking forward to reading all of Zack Eswine’s The Imperfect Pastor.
Here he writes about the way that aspiring to the work of a pastor is a long-haul commitment that cannot succumb to the temptations of haste or instancy:

…imagine loving God and others through the desolations of life. Desolation cannot easily endure an accelerated pastoral pace. This explains why many of us have no patience for pastoral care. Broken bones and minds are not hurry prone. Burned skin or victimized souls have to get to the miserable itching in order to heal, and we who wait by the bedside must wait some more. Death, grief, loss, recovery from addiction, as well as emotional or physical trauma, parenting special-needs kids, adjusting to chronic illness, depression, disability, or disease — all of these desolations are handled poorly when “efficiency” and “quantitative measures” are required of them. To the important pastor doing large and famous things speedily, the brokenness of people actually feels like an intrusion keeping us from getting our important work for God done. I write that last sentence, and it undoes me. Reread it. Then fall with me, won’t you? Fall to your knees with me before the Savior. He is the lifter of our heads. We need this gracious lifting, for we haven’t even spoken yet of how words like instant and impatient offer us no resources to handle the mattering thing of loving our enemies in ministry. And make no mistake: eventually you will have to learn this hardest of neighbor loves too.
As a rule then (and this often surprises us), haste is no friend to desire. The wise man says so, because “whoever makes haste with his feet misses his way” (Prov. 19:2). His point is clear enough. Haste has a habit of not coming through on things that truly matter.
In a crisis it can help. But when it comes to understanding, sorting out, and fulfilling the desires of a human soul, haste constantly and legitimately gets sued for malpractice. Haste offers immediate promises to our desires for a mate or ministry or work or our kids, but haste actually can never deliver on these promises for what is most precious to us.
The point I’m now making is this. Our desire for greatness in ministry isn’t the problem. Our problem rises from how the haste of doing large things, famously and as fast as we can, is reshaping our definition of what a great thing is. Desire greatness, dear pastor! But bend your definition of greatness to the one Jesus gives us. At minimum we must begin to take a stand on this one important fact: obscurity and greatness are not opposites.
Zack Eswine, The Imperfect Pastor, Crossway, 2015, pp 28-29.