This is why self scan is my favourite. Just scan stuff on your phone as you walk around, pack your bags ahead of time and the only time the staff need to get involved is age checking alcohol or painkillers, if there is some problem you had scanning something or if you get a random rescan request (which is admittedly horrible as it makes you feel like a criminal when they find the one item that didnt scan right). So much easier and faster than any of the other methods.