If you want to persuade someone, it is best do whisper in their right ear, as this article suggests.
Both men and women (72%) prefer to use their right ear when listening to their conversation partner, and a majority of us also hold our mobile phones to our right ears.
What may at first seem rather strange begins to make sense on closer investigation:
Language is processed by the left-hand side of the brain, which receives its input from the right-hand ear. Therefor, showing a preference for using one's right-had hear to listen to a conversation isn't all that strange!