There are three types of impossible:
1. Statistically impossible, as in "It could be true once in a trillion billion times." This is the basis for agnosticism.
2. Fundamentally impossible, as in it couldn't be true without being contrary to such basic observations about the universe as entropy.
3. The third form is the impossibility by paradox, in which there is a mathematical or logical problem that is insurmountable.
Religions manage to self-destruct on all three forms of impossibility.
That doesn't stop me being nice to the fundamental patients of the religious fringe, at least until they start making death threats because I don't believe in (insert mythical beast or being here), or want to run the world into a ditch because a book by paleolithic goat herders told them to do so.