I get tired of having to assert in many words something that Christopher Hitchens has already stated quite well.
Hitchens' Razor: what can be asserted without evidence can also be dismissed without evidence.
This phrase is found in a Christopher Hitchens Slate article on Mother Teresa. To me it is a beautiful phrase that can be used to save a lot of time, as chasing down why someones non-supported statements are wrong is wasteful. It puts the onus back onto the asserter to give evidence to support their baseless assertion. Much less tiresome than the refuter having to argue, yet again, why it is that when there is no evidence for an assertion it is not the refuters job to find it for them.
So, when someone tries to tell you that faeries live at the bottom of the garden, just because! Just apply Hitchens' Razor.
Important Edit: The correct use should be Hitchens's Razor. Please see my entry for the correction.