Jesus, knowing that the Father had given all things into His hands, and that He had come from God and was going to God, rose from supper and laid aside His garments, took a towel and girded Himself. After that, He poured water into a basin and began to wash the disciples' feet, and to wipe them with the towel with which he was girded. - John 13:3-5 (NKJV)Service can be difficult because it can be uncomfortable. Comfort means doing what I want to do when and where I want to do it. Service is uncomfortable because I have to do what others need when and where they need it.
In the story above, Jesus is able to do what others would see as uncomfortable or even demeaning. How? I believe he can serve radically because he understands the identity and purpose of himself, God, and others. With that knowledge, he has the strength to put his personal comfort aside and serve.