I've always found Romanian author and philosopher Andrei Codrescu vaguely annoying, but he's very good in the interview below on spirituality. He also has a great bit about argument and candor that we at Wit heartily agree with.
"Historically, as we all know, true shamans and spiritual people have been shunned by most communities. They have been ostracized. The shamans had to live in a tree and they were dirty and frightful people, and when they came to the edge of the village, it was only the fact that they had spiritual and healing powers that kept the people from beating them with sticks and destroying them.
And it seems to me that the shaman's perspective is the one from which to question the genuineness of any spiritual package that doesn't transform you into a complete freak who has to eat worms and live in the desert, that allows you to still live in your community and not be an outcast. Because a palatable spiritual package, to me, runs the danger of not having enough energy or of not being spiritual enough—an effect of being pretty much just a dilettante's dabbling in superstition.
I really think that the genuinely spiritual person is dangerous, and charged with a kind of frightful energy and antisocial power. And when they appear, they will be shunned."