Cognitive biases are errors in thinking or patterned biases in judgment that occur systematically in certain situations. Cognitive distortions are an example of evolutionarily developed mental behavior. Some of them serve an adaptive function in that they promote more efficient actions or faster decisions. Others seem to stem from a lack of appropriate thinking skills, or from the inappropriate application of previously useful skills. There's no end to the mistakes we make when processing information, here are 10 of the most common ones.