While I agree with the concept, here are a couple of my thoughts after living here in Texas for about 40 years. A wave in a large city such as Houston, Dallas, San Antonio or Austin is usually done with one finger extended, which in extreme cases may cause gun fire later. A wave in rural areas of the state is a friendly gesture and a way to say Hello to your fellow motorist and is usually returned in kind. Some people participate some do not. I usually wave to fellow Ram owners in rural areas and wave to owners of street rods and nice go fast boats in appreciation of well kept machines. In large cities I just mind my own business and always carry just in case.
Jay