In reading the words of Jesus, I sometimes say Wow!! He laid down a tough rule when he said love one another, even enemies. In fact, the "rules" of Jesus appear harder than those of Moses, and the Mosaic prescriptions stymied the Hebrews throughout biblical history.
If the new "rule" makes me feel guilty all the time because I don't measure up, how is that an improvement from Old Testament times? The daunting nature of the Golden Rule is something any proclaimed follower of Jesus must face. Mostly, I have considered these words to be some sort of insuperable commandment which sounded great when I was the recipient of grace but probably not so, if I had to be the giver. With that sort of gut reaction to what I perceived as a divine commandment, the resulting mental state was always frustration, guilt, and a general feeling of inadequacy. I deal with enough of that already, so why does it need to be a part of "all things new" (II Corinthians 5:17).
Maybe we don't have to see love as an obligation, given the words of Jesus. Instead we can view it as an opportunity presented by Jesus, one we are free to accept or reject. We don't have to feel guilty if we turn down this opportunity, merely prepared to deal with whatever results from acting in the way that feels more comfortable or normal to us. In other words, if not loving works, then just do it. We are going to anyway, until such time that not loving ceases to work.
Despite what I said about feeling guilty, I reject the idea that as supposed Christians we can fail in loving and still feel all smug and sanctimonious relative to others, especially those we fail to love. Christian life is first and foremost an exercise in humility. There is no place for the self exaltation which seeps into so many practices supposedly identified with Christianity.
If what I have suggested is true, what then? I believe that Love/God is always there calling us to a higher self, but if we are not ready yet, then we just move on without it. All things come when the time is right. Life is generally a gradually growing awareness, not a sudden epiphany.