It is difficult; but not impossible.  Though sometimes we reflect on the hurt that they have done, but we just have to calm ourselves with the knowledge that Jesus forgave the Romans when crucifying Him, for He said, "Lord forgive them for they know not what they are doing".  It takes alot of compassion, self discipline, awareness and a forgiving heart.  In addition our enemies make us alert and stronger!

When we love our enemies, our reward shall be great, and we shall be called children of the highest.  In addition, the thanks we will get; being called a child of God and most importantly to be like God.