Jesus says, "But I say to you, Love your enemies and pray for those who persecute you, so that you may be sons of your Father who is in heaven... For if you love those who love you, what reward do you have?
Do not even the tax collectors do the same? And if you greet only your brothers, what more are you doing than others? Do not even the Gentiles do the same?"
Matthew 5:44-47 (ESV)

In his book, Mere Christianity, C. S. Lewis points out that it is easy to love the likeable. However, the virtue of "charity" comes by choosing to act lovingly toward the unlikable. Lewis writes  

. . .'Charity' now means simply what used to be called 'alms'-that is, giving to the poor. Originally it had a much wider meaning. . . Charity means "Love, in the Christian sense." But love, in the Christian sense, does not mean an emotion. It is a state not of the feelings but of the will; that state of the will which we have naturally about ourselves, and must learn to have about other people.  

I pointed out in the chapter on Forgiveness that our love for ourselves does not mean that we like ourselves. It means that we wish our own good. In the same way Christian Love (or Charity) for our neighbors is quite a different thing from liking or affection. We "like" or are "fond of" some people, and not of others. It is important to understand that this natural "liking" is neither a sin or a virtue, any more than your likes and dislikes in food are a sin or a virtue. It is just a fact. But, of course, what we do about it is either sinful or virtuous. 

Natural liking or affection for people makes it easier to be "charitable" towards them. It is, therefore, normally a duty to encourage our affections-to "like" people as much as we can (just as it is often our duty to encourage our liking for exercise or wholesome food)-not because this liking is itself the virtue of charity, but because it is a help to it. . . . 

. . . The rule for all of us is perfectly simple.  Do not waste time bothering whether you "love" your neighbor; act as if you did. As soon as we do this we find one of the great secrets. When you are behaving as if you loved someone, you will presently come to love him. If you injure someone you dislike, you will find yourself disliking him more. If you do him a good turn, you will find yourself disliking him less. . . 

Consequently, though Christian charity sounds a very cold thing to people whose heads are full of sentimentality, and though it is quite distinct from affection, yet it leads to affection. The difference between a Christian and a worldly man is not that the worldly man has only affections or "likings" and the Christian has only "charity." The worldly man treats certain people kindly because he "likes" them: the Christian, trying to treat every one kindly, finds himself liking more and more people as he goes on--including people he could not even have imagined himself liking at the beginning.¹  

As Valentine's Day approaches, let's not waste time on cheap talk about "love," let's act lovingly toward all, including those we don't naturally like. And as we do, we might be surprised to discover we've grown to like them.