...me so much.
It really gets my goat.
Many times I have wanted to go to the person and press down on that bouncy leg to stop it. I have to shut my eyes or look away.
Most people don't do it quite so vigorously - although some do!
(Of course I apologise if you do it yourself.)
And why do people do it anyway?
(Yes, I know there are more important things in life.)