As the first fruit of the Spirit mentioned by the apostle Paul, it is reasonable to assume that it (i.e. Love) must be the most important (see also I Corinthians 13:13). With that said, we should do everything we possibly can to make sure that we have this fruit of the Spirit in our lives. In fact, Paul said in I Corinthians 13:1-3 that if we don't have love, nothing else that we accomplish even matters.

"He that saith he abideth in Him ought himself also so to walk, even as He walked."

               -I John 2:6

Jesus was the ultimate example of love. Though we had never done anything to deserve His grace, He poured it out freely upon each of us by dying on the cross "...while we were yet sinners." (Romans 5:8) As John said, if we are going to follow Christ, we must "walk as he walked", which means we must love those around us just like He did - even if they have done nothing to deserve it. In reality, loving only those who deserve our love is nothing special at all; loving those who don't deserve it is the mark of a true Christian (John 13:35), because it is evidence of a super-natural power working within us.

"He that loveth not knoweth not God; for God is love." 
                                        -I John 4:8 

If God is love, and we don't have love, then we don't have God. We must love both friends and enemies, those we know as well as those we don't know, if we intend to please God.