Haven't went through all the posts, since most are the same responses. You have to remember that one of the key elements of riding is to always be aware of your surrounding and to pay attention to the road. So when someone doesn't "wave" back at you or throw a peace sign, they may not be looking/watching for someone on the other side of the road trying to wave at them, but instead watching the cagers driving on all sides of him. Also, i would suspect the reason you do a "low wave" is because waving high can also be a signal to someone that you are wanting to take a right hand turn.