To go a little deeper, FNG, part of the reason many people fly is for the freedom. That freedom is restricted by the radio and, God knows, there are enough restrictions placed our flying already.
There was once an accepted gesture, I think I mentioned it earlier, waggling the wings; could mean anything you want it to mean. And a little waggle back in reply...being a member of the brotherhood of airmen and all that.
Why don't people do that any more?