Social engineering continues to pose a significant threat by manipulating human psychology, thereby bypassing technical safeguards. Attackers exploit cognitive fallacies, including authority, trust, and reciprocity, to coerce individuals into disclosing sensitive data or granting unauthorised access. Social engineers can undermine rational judgement by combining deceptive strategies with emotional triggers, rendering even the most robust firewalls and encryption ineffective. This chapter investigates the distinction between persuasion and manipulation, illustrating how assailants employ common heuristics to develop persuasive tricks. It emphasises the constraints of technology-focused countermeasures by conducting an analysis of case studies and psychological research.