Don’t worry so much about whether you're being witty or charming. And don’t sweat the fact that you’re not looking your best before you meet your boyfriend’s grandmother or your sister’s boss for the first time.
If your goal is to make a good first impression just be polite and extend your hand in greeting. A study discussed on Science Daily suggests the simple, old-fashioned handshake is the foolproof technique for winning you positive points with a stranger.