A fatal error.
Never mistake a sphinxlike silence for sophistication when it just might be someone calculating their next move. Don't delude yourself that just because someone isn't immediately asking you about personal matters in order to satisfy their own prurient interests that they are not waiting for the exact time your guard is down to sneak in a seemingly innocuous inquiry. For whatever reason, this day and age of instant communication seems to have engendered a society where the exchange of information has become as precious a commodity as it was in pre-Revolution France. We are all now constantly milling about in that hall of mirrors, waiting to get near an orange tree and see what the news is.