Every con, big or small, relies on one thing: distracting you from the obvious. One of the most obvious facts in a questionable situation is when you're approached by a stranger.
De Becker says that often times criminals will converse with their victims a little too much, feeding them too many details about false experiences in order to distract their victims from the obvious fact that the person doesn't know them at all.
Moreover, the reason criminals give too many details is a telling sign of their malintent:
"When people are telling the truth, they don't feel doubted, so they don't feel the need for additional support in the form of details. When people lie, however, even if what they say sounds credible to you, it doesn't sound credible to them, so they keep talking," de Becker writes.