Fairy Liquid contains silicon which is why the advert used to say 'for hands that use fairy can be as soft as your face....'
It leaves a coating of silicon. Like dishes, it's looks ok to start with but after a while, that good old silicon leaves smear marks and dust sticks to it.
Also, I can always tell any new customers shop window that has been done previously with fairy liquid, it bubbles up like anything. That means good old fairy leaves a residue.