Buddhist arahants are a vision of human perfection; these individuals have purified themselves so totally that they are immune from the vices of ordinary mortals. Yet is this ideal attainable? It has been argued, for instance, that no true arahants exist in the modern age, that this ideal was only attainable in the Buddha's time.
Buddhist teachers, even those who are seen by others to be enlightened, often point out that they are not perfect and have failings. The history of Buddhism in the West is rife with stories of Buddhist teachers who showed that they were not perfect in the most egregious manner by indulging in sexual misconduct with their students. Many have been disillusioned by this kind of behavior of teachers whom they previously revered.
I am sometimes surprised by the reaction of those to whom I teach meditation when I admit to my own failings. I acknowledge that I am a leaking boat that requires constant bailing just to stay afloat. One of my clients once asked, "Is this all just salesmanship then?" My reply: "You should have seen me before I practised meditation!"