If you are looking at a friend three meters (ten feet) away, at the other end of the room, you are not seeing her as she is “now”; but rather as she “was” a hundred millionth of a second ago. [(3 m) / (3 × 108 m/sec) = 1/(108 / sec) = 10–8 sec, or a hundredth of a microsecond. In this calculation we have merely divided the distance by the speed to get the travel time.] But the difference between your friend “now” and now minus a hundred-millionth of a second is too small to notice.
