| Daniel | Ariely | Behavioral economist. |
| Lance | Armstrong | Professional road racing cyclist. |
| Sissela | Bok | Philosopher. |
| John | Edwards | Former US senator. |
| Anne | Frank | German diarist. |
| Sam | Harris | Narrator and author. |
| Ronald A. | Howard | An extraordinarily gifted professor at Stanford. |
| (Immanuel) | Kant | Philosopher. Believed lying was unethical in all cases. |
| Clint | Korver | A doctoral student. |
| Jeffrey | Macdonald | A green beret physician convicted of murdering his pregnant wife and two daughters. |
| Janet | Malcolm | Writer. |
| Joe | McGinnis | The best-selling author of Fatal Vision. |
| Eliot | Spitzer | Former Governor of New York. |
| Lao | Tzu | Chinese philosopher. |
| Andrew | Wakefield | Physician. |
| Anthony | Wiener | Former US representative. |
| Tiger | Woods | Professional golfer. |
| Daniel | | Sam's friend. |
| Derek | | Gina's husband. |
| Gina | | Stephanie's friend. |
| Jessica | | Lucy's fiend. |
| Lucy | | Jessica's friend. |
| Sita | | Sam's friend who lied about where she got her gift for another friend. |
| Stephanie | | Gina's friend. |