1. “I can’t prove there is a God, but you can’t prove there isn’t.” While this is true as far as it goes, the theist begs the question, assuming that the existence of God is the default position and that it is up to the skeptic to assume the burden of proof. While formally true that one can’t prove a negative, it is up to the person who asserts a positive to make with the evidence. The negative is the default position. If you don’t see evidence for something, why shouldn’t you go on as if that thing didn’t exist?
This argument is particularly frustrating for the objective questioner who values clear and distinct ideas, and really makes religion look like a self administered form of mind control, since religionists just can’t seem to see what’s clearly wrong with it. It’s as though you were pointing at a spot on a piece of paper, and they look ahead of it and say “I don’t see a spot.“ Then you point again, and they still insist that there is no spot to be found, and you’re bad and crazy for saying otherwise.
Related to this is the assertion that if we can’t know something as a certainty (here defined as 100% certainty, a state which simply doesn’t exist in the real world), then we are free to believe absolutely anything we like about it, regardless of how unsupported it is by any evidence. Even if the preponderance of evidence that does exist supports the other position. This point of view is prevalent among lay Creationists disputing with Evolutionists. No one perspective on evolution is 100% certain. Evolutionists disagree with one another on the details. No one was there to see evolution take place. Therefore, it is perfectly acceptable for me to believe and teach that the Earth was created by magic 6,000 years ago (or less than 10,000 years ago, if the creationist is particularly open minded) even though some (a lot, actually) evidence exists for evolution and none exists for creation.
Theists, please stop saying this stuff.