The only time that maintaining the wall that separates church and state proves difficult for me is when I go over certain works of literature in my senior English class. So much of what is part of the curriculum, particularly from the years right before the Enlightenment, is heavily mired in religious and metaphysical exploration that an English teacher who wants to do justice to the works simply cannot discuss them without also exploring the motivations for their creation. Perhaps you can swing John Donne's "Meditation 17" towards a more humanist philosophy, but is that then a sincere exploration? I don't really think so. Then we get to works like Paradise Lost and Pilgrim's Progress. Filtering out the religious overtones on those would be like showing reruns of The Sopranos or Deadwood on the Family Channel by bleeping out the cussing. You'd lose all meaning, and the bleeps would run together so much that every dog within earshot would start howling. So I try to focus mainly on the literary merit, and when it comes to the metaphysical content, I simply try to pose questions that I leave up to the students to answer for themselves.
Apparently I do too good a job in masking my own beliefs. A senior yesterday if I was trying to suggest that Christianity is the one true religion.
Yeah, I got a good chuckle out of that one, too.