We all lie. But even savvy parents may blanch at the news that 80% of high school students in a new survey admitted to lying to their parents about something "significant" in the past year. The finding is in line with past reports and is not the most shocking thing in the survey: After all, 59% of the 43,000 teens surveyed by the Josephson Institute of Ethics said they'd cheated on a test, and 27% said they'd stolen from a store.

But it is a reminder that parenting teens sometimes requires separating fact from fiction — and harmless fibs from dangerous deceptions.