Many studies have shown that people tend to exaggerate their own positive characteristics and abilities. For instance, studies have shown that most drivers think they're a better-than-average driver. Psychologists call this the state of "illusory superiority" (explored in this illustration as well).

Recently (2014), a team of British researchers tested this common "better-than-average" tendency by surveying 85 convicts at a prison in South East England about their pro-social traits. The inmates were aged 18 to 34 and the majority had been jailed for acts of violence and robbery. The inmates completed questionnaires anonymously and in relative privacy. Here's what the study concluded:

Compared with "an average prisoner" the [convicts] rated themselves as more moral, kinder to others, more self-controlled, more law-abiding, more compassionate, more generous, more dependable, more trustworthy, and more honest. Remarkably, they also rated themselves as higher on all these traits than "an average member of the community," with one exception—law-abiding. The prisoners rated themselves as equivalent on this trait relative to an average community member.

Possible Preaching Angles: Sin; Self-righteousness; Self-justification—Perhaps we'd like to think that we are "better" than these prisoners, that we would be honest about our faults and our virtues, but in many ways we do the same thing—we over-estimate our "goodness" and self-justify our good qualities while minimizing our bad qualities.