From A Year With C.S. Lewis:

Well, how exactly do I love myself?

Now that I come to think of it, I have not exactly got a feeling of fondness or affection for myself, and I do not even always enjoy my own society. So apparently ‘Love your neighbor’ does not mean ‘feel fond of him’ or ‘find him attractive.’ I ought to have seen that before, because, of course, you cannot feel fond of a person by trying. Do I think well of myself, think myself a nice chap? Well, I am afraid I sometimes do (and those are, no doubt, my worst moments) but that is not why I love myself. In fact it is the other way round: my self-love makes me think myself nice, but thinking myself nice is not why I love myself. So loving my enemies does not apparently mean thinking them nice either. That is an enormous relief. For a good many people imagine that forgiving your enemies means making out that they are really not such bad fellows after all, when it is quite plain that they are. Go a step further. In my most clear-sighted moments not only do I not think myself a nice man, but I know that I am a very nasty one. I can look at some of the things I have done with horror and loathing. So apparently I am allowed to loathe and hate some of the things my enemies do.
–from Mere Christianity.