@vkc I was addicted to middle-click paste for most of my computing history, but then I switched to a trackball due to RSI, and the habit mostly ended immediately (as the middle mouse button isn't in the middle anymore, so there's no muscle memory).

I guess it depends on what replaces it, as to whether it'll surprise me and make me angry some day. Autoscroll would be a terrible thing to happen to the middle mouse button. But, I guess as long as I can configure it, I don't care that much.