You learned about the requirement to give your flying passengers a briefing before you start your flight, right? And you make sure that you conduct a briefing each and every time you take someone with you in the plane, right? The requirement to conduct a passenger safety briefing is found in 14 CFR 91.517.
As with other things in aviation, such as with weather minimums, complying with the minimum requirment makes your flight legal but it is not necessarily the safest or smartest way to operate.
The AOPA Air Safety Institute has published a video (time 16:24) time that gives you much more to think about when conducting your passenger safety briefing.
You may download Passenger Safety Briefing Card (pdf) here.