The Sermon on the Mount, however, does not offer a clear view of what makes for a good life. Many seem to think Jesus is saying little more than be nice to everybody. Others see a call to a heroic life of total non-resistance or self-sacrifice. Still others hear him as requiring little more than an enhanced version of the Ten Commandments (e.g., avoiding not only murder but also anger, not only adultery but also lustful desires).
Almost all Christians ignore many of the things Jesus said on the Mount. Who literally takes no thought for their lives or for tomorrow? Who never resists evil? Who gives to anyone who asks? Who says “Hit me again” to an unjust attack? There may be ways of integrating such injunctions into our morality without reducing them to banalities, but the bare text of Jesus’ sermon doesn’t tell us how to do this.
Yeah, it's true; a literal belief in the imminent end of the world does tend to render the advice you offer people a bit short on nuance and practicality. Seriously, it amazes me how much effort people put into trying to salvage something inspirational from this dreck. Even if you set aside the irrelevance of his preaching once the centrality of the apocalypse is removed, there's just nothing profound there. As J.L. Mackie said:
Richard Robinson has examined the synoptic gospels as the best evidence for Jesus's own teaching, and he finds in them five major precepts: "love God, believe in me, love man, be pure in heart, be humble." The reasons given for these precepts are "a plain matter of promises and threats": they are "that the kingdom of heaven is at hand," and that "those who obey these precepts will be rewarded in heaven, while those who disobey will have weeping and gnashing of teeth." Robinson notes that "Certain ideals that are prominent elsewhere are rather conspicuously absent from the synoptic gospels." These include beauty, truth, knowledge and reason:
As Jesus never recommends knowledge, so he never recommends the virtue that seeks and leads to knowledge, namely reason. On the contrary, he regards certain beliefs as in themselves sinful...whereas it is an essential part of the ideal of reason to hold that no belief can be morally wrong if reached in the attempt to believe truly. Jesus again and again demands faith; and by faith he means believing certain very improbable things without considering evidence or estimating probabilities, and that is contrary to reason.
Jesus says nothing on any social question except divorce, and all ascriptions of any political doctrine to him are false. He does not pronounce about war, capital punishment, gambling, justice, the administration of law, the distribution of goods, socialism, equality of income, equality of sex, equality of colour, equality of opportunity, tyranny, freedom, slavery, self-determination, or contraception. There is nothing Christian about being for any of these things, nor about being against them, if we mean by "Christian" what Jesus taught according to the synoptic gospels.