"I don't buy it."

From the preface of "What the Dog Saw":

Nothing frustrates me more than someone who reads something of mine or anyone else's and says, angrily, "I don't buy it." Why are they angry? Good writing does not succeed or fail on the strength of its ability to persuade. ... It succeeds or fail on the strength of its ability to engage you, to make you think, to give you a glimpse into someone else's head -- even if in the end you conclude that someone else's head is not a place you'd really like to be.