There are many reasons why Christ's teaching is not understood...
But the principle reason, which is the source of all the other mistaken ideas about it, is the notion that Christianity is a doctrine which can be accepted or rejected without any change of life.
I found this here (a new blog to keep up with!). And immediately coupled it with Wittgenstein, a quote I've used more than once ("Do I repeat myself? Very well then, I repeat myself. I am finite, I contain recursivities."--Walt Whitman).
Christianity is not a doctrine, not, I mean, a theory about what has happened and will happen to the human soul, but a description of something that actually takes place in human life. For 'consciousness of sin' is a real event and so are despair and salvation through faith. Those who speak of such things (Bunyan for instance) are simply describing what has happened to them, whatever gloss anyone may want to put on it.Ludwig Wittgenstein, "Ethics, Life and Faith," The Wittgenstein Reader, ed. Anthony Kenny (Oxford, Blackwell Press 1994).
And an excuse to mention this, which, although it is four years old, is still timely. Not to mention pretty darned good.