Greeks are so cryptic

I was ripping along 101 when this hero in a Hyundai Santa Fe decided that I only needed to be doing about 55mph in the passing lane. Eventually she conceded and moved to the travel lane, but gave me a hand gesture that looked exactly like this as I passed her. I could tell she was Greek by her discerning features and dark hair, and somehow that may play into all of this. But as to exactly what this cryptic symbol means – I have no idea whatsoever and it will haunt me for days more as it already has.