Is Comfort a Good Thing?

I was having a conversation with God today where I told him how I had been looking forward to this year and being comfortable with where I was and what I was going to be doing. I talked with him about the fact that he had not allowed this preconceived concept of my life to continue and my struggle to accept the way he is growing me.
Later in class my professor declared that a leader will "understand contentment and refuse to live for comfort." It was like God was hitting me over the head - if I didn't get it in my earlier talk with him, I got it then: I am not to live for comfort. I am to pursue God and that entails growth, and growth is never comfortable, yet you can be content in it.
In God's push to get me outside my comfort zone this year he has revealed pride in my heart and areas of vast unbelief in God's goodness, faithfulness and love. God knows my heart and knows how I needed to grow and mature in these areas, yet it has not been very comfortable (yet, at the same time it is very good).
I can be content where God has me and what he has me doing, but if I ever drift into being "comfortable" - into failing to rely on the Spirit, ceasing to seek God in prayer and through the word - I will cease to grow and mature in my relationship with Christ. I will cease to have a deep and intimate relationship with Jesus.
Jesus never called us to a comfortable life, he called us to obedience and surrender, and while there is great contentment in following him, it is risky and uncomfortable to offer him your all.