Interpreting Dog-tail Wags

Human scientists have made progress in interpreting how we dogs wag our tails. In case you did not know, it is more complicated than just: "wagging tail, happy dog". Humans who know many dogs are aware of this, of course. I will not write more about it now, it is better if you read what a human journalist write. A human must be better on explainign this to other humans than I, as a dog, am.