When people seek to persuade others to purchase a particular product or service, they often give an extremely favorable review of it as a means of doing so. Despite the intuitive appeal of this strategy, the current research demonstrates that a moderately positive review is sometimes more persuasive. In particular, when the perceived default evaluation in a given context is extremely positive, moderately positive reviews that deviate from that default can become more persuasive. In contrast, when the perceived default is moderately positive, extremely positive reviews tend to be more persuasive. This deviation effect occurs because reviews that deviate from the perceived default are believed to be more thoughtful, and thus accurate, which enhances their persuasive impact. This effect is demonstrated in eight experiments set in a diverse range of consumer contexts.