Mark Zuckerberg is the CEO of Facebook. The document discusses two incidents: 1) Zuckerberg's 2013 commencement address at Harvard where he emphasized the importance of building community and giving everyone a sense of purpose. 2) Zuckerberg testifying before Congress in 2018 regarding the Cambridge Analytica data scandal. During the testimony, Zuckerberg apologized but some of his body language like shaking his head when denying accusations did not match his words, potentially indicating a lack of truthfulness. His handling of difficult questions showed discipline but some non-verbal cues like fake smiling and covering up topics quickly raised questions about his sincerity.