I was trying to pick only one tissue paper from a tissue box. But each time it comes out with 2 or more pieces. I just fed up separating it one by one after picked it up.
The reason you are getting two tissues out instead of one is because the plastic lining that regulates the tissues leaving the box was damaged. To repair the slit of plastic you could use plastic food wrap to reshape it's opening to be narrow enough to hold back a secondary tissue from coming out of the box.