Most frustrating Fallacies that Religious people bring up?

[Faith No More]

Not so much a fallacy, but I hate it when you're whittling down their various claims by asking how they know them to be true and they resort to attacking the very axioms we use to survive every day life, i.e. natural laws are consistent, in order to obfuscate the whole argument into an obscure, deeply philosophical discussion and show that much of the very knowledge we have is resting upon shaky foundations. Then they go, "See! We don't really know anything, so I can just assert that my arguments are valid without actually justifying them. And furthermore, just inserting the unfalsifiable solution of god into the equation solves all of those pesky philosophical questions that you non-believers still have to struggle with."

ETA: 9,000, bitches!