Not Flipping Off Your Fellow Drivers

So, when I'm merging into traffic I always give the 'thank you' wave to any driver kind enough to let me slip from the on-ramp into the traffic flow. When I wave 'thanks!' to the gracious driver behind me, I always give a whole hand wave and spread my fingers apart so they won't think I'm flipping them off instead of thanking them. Is it just me or does anyone else worry about this?