In my experience, it is much easier to act like a Christian than it is to react like one. Most of us are good actors -- we can play the part. But our reactions reveal who we really are. And maybe that's why Jesus focused so much of His teaching on reconditioning reflexes.
Pray for those who persecute you.
Love your enemies.
Bless those who curse you.
If someone forces you to go one mile, go with him two miles.
If someone strikes you on the right cheek, turn to him the other also.
Mark hit the nail on the head! I find this so true. I can be going around "perfectly holy" all day, and then someone does something to me or something doesn't go how I'd planned and the reactionary self rears its head and too often takes over and replaces my "perfectly holy" mask.