Like all humans, M/EEG researchers commit certain fallacies or mistakes in reasoning. This article surveys seven well-known but still common fallacies, including reverse inference, hasty generalization, hasty exclusion, inferring from group to individual, inferring from correlation to causation, affirming a disjunct, and false dichotomy. These fallacies are illustrated with classic EEG research by Libet and collaborators, but many researchers (not just Libet) continue to commit them in all areas of research (not just M/EEG). This article gives practical suggestions about how to spot and avoid each fallacy.