As I write this, I have just turned 45 years old and have served for over 22 years as a pastor in two congregations. Half of my existence on this earth has been spent pastoring. I have been changed and transformed by this experience. Here are a few of the things that I've learned along the way:

The relationship between authority, responsibility, and control.
Authority and responsibility are two sides of the same coin, and if they ever get disconnected, trouble follows. People who don't take responsibility should not be given authority. Those who have been given authority must take responsibility. But neither authority nor responsibility is the same as control. You may have responsibility to others, and you may have authority in a church, but you only have control over yourself. Self-control is a fruit of the Holy Spirit's presence in your life. The only person that you should exercise control over is yourself.

Your presence enhances your credibility.
Pastoral ministry is a balance between DOING and BEING. Often, we are doing ministry: preaching, preparing, leading, serving, etc. Sometimes we must set aside the DOING in order to BE present. I was present at plenty of church services, meetings, events, etc. where I had no responsibility. I attended services even if I wasn't preaching. I sat in meetings just to provide support. I went to birthday and graduation parties. I worked in the church office even when I could have worked from home. I sat in silence with grieving people. In those moments, I didn't do much other than help people know they were not alone. This actually enhanced my credibility when it was time for me to return to doing my responsibilities.

Church planting is a front-row seat to practical ecclesiology.
A lot of people have some pretty neat ideas about the church. But it's not until you plant and/or lead a church that you really learn how stupid most of those neat ideas are. When I studied ecclesiology (the study of the church) in college, my mind was filled with neat ideas and cool new initiatives that I would try when it was finally my turn to lead. Over time, I found myself giving up on the search for "new" ways of doing church, and I began to return to time-tested, ancient principles of church life. I started familiarizing myself with church history, the Didache, the creeds, and more. I stopped trying to stay up to date on every new ministry model fad that came and went. This was ultimately good for my soul and our church.

Ministry will kill your ego.
When I moved to Philadelphia, I made it a point to meet with older pastors who were already doing the things that I wanted to do. One of them looked me square in the eye and said, "Your neighborhood is a graveyard for pastors."
In a way, he was right. Pastoral ministry didn't kill me, but it did kill my ego. Now that I'm the older pastor, here's my advice to younger pastors: If pastoral ministry is killing your ego, that's not a reason to leave; that's a reason to stay. Your ego needs to die.
To my fellow ministry vets, I would say, be careful sharing your horror stories with the new guys. You don't want them to come into their experience with your second-hand pain and disappointments. Share your wisdom, but not your cynicism and bitterness. Your cynicism and bitterness are just your ego refusing to die.

Human beings are composed of body, soul, and spirit, and you have to know how to care for all of those aspects of the human experience.
God is sanctifying us, body, soul, and spirit (1 Thess. 5:23). Most people understand what the body is, but not the distinction between the soul and spirit (Heb. 4:12). The soul is your mind, will, and emotions (aka thoughts, decisions, feelings). Your soul says, "I think, I want, I feel."
Your spirit is distinct from your soul, though the two interact with each other all the time. Before coming to Christ, your spirit is dead. After coming to Christ, your spirit is regenerated, or born again. Your spirit is now united with Christ's Spirit, and from this union flows all of your authentic walk with Jesus. Your spirit is convicted of sin, welcomes repentance, is drawn to pray, operates in gifts, discerns evil, and more.
Pastors need to know how to minister to all three areas because God is actively sanctifying us in all three.

God anoints authenticity.
A lot of life is learned through modeling and examples. I learned to swing a baseball bat by watching Ken Griffey Jr. (I didn't get the same results, though). Following the model and example of others is a great way to learn, but we want to be careful not to become a copy of someone else. There is more anointing (Spirit-empowerment) in being yourself than in trying to copy someone else's anointing. Every time that I feel that I must perform, or put on a show, I have to stop and tell my soul to just be myself. God anoints authenticity.

A diverse, Spirit-filled congregation is better than any church program.
I could not begin to guess how many books, conferences, classes, or programs I have engaged with in the name of becoming a more faithful disciple of Jesus. Some were more effective than others, but none were as effective as being part of a diverse, Spirit-filled congregation. The people, practices, and perspectives encountered in a diverse congregation have caused me to reconsider my own conclusions so many times. Of course, this really only works when there is a mutual commitment to live according to God's Word and to follow Jesus.

The importance of plodding.
I was a Lead Pastor for over 18 years. That's over 6,500 days. Of those 6,500 days, maybe 100 of them were remarkable. There were a few days every year that were life-altering for our congregation: an especially dynamic service, a crisis, a healing, a significant wedding, a tragic funeral, a prodigal returning, miraculous provision. These things didn't happen every single day, but they happened often enough to keep us on our toes.
Most days were pretty mundane. I arrived in the office, made a cup of coffee, pushed "Start" on the Roomba in the sanctuary, opened my laptop, and got to work. We had exciting conversations about who left their sweater in the sanctuary, the weather forecast on the day of an outdoor event, repairs around the building, and who seemed to be absent from church for a few weeks. I used to think that these things were unspiritual, until I read the accounts of the priests in the Old Testament and how they carried out many of the same mundane, daily tasks each day, at God's command. This was actually a sign of diligent care for God's people.
Remaining faithful in the daily mundane tasks of ministry is called "plodding." It's putting one foot in front of the other, even when it feels monotonous. Another urban church planter named A.B. Simpson wrote a hymn about this. The hymn was called "Plod" and one stanza said:

Let us plod, steadily plod,
All along the way;
Zeal my fire and hope inspire,
But plod will win the day

We grow by participating.
I was transformed and changed by pastoring, but really, it was by serving. You can be transformed by teaching children's church for 40 years, or serving as a youth leader for a summer, or taking a risk to sing on a worship team, or making a sacrifice to give generously. You don't actually have to be in pastoral ministry to experience transformation, but you do have to participate and serve in the Kingdom. We have to participate to grow.

It is impossible to think too highly of Jesus.
I can think too highly of myself, my experience, my culture, my denomination, or my theology, but it's impossible to think too highly of Jesus. In fact, no matter how highly you currently think of Jesus, it's still not high enough. Go higher. Think more highly of Him. Elevate Him higher in your heart and mind. Exalt Him.