The thing is, it's not like this happens once every now and then, it's every time I'm in a shop - I either end up behind the bastard who decides to pay in pennies, or I get the till operator who's obviously been doing the job since about five minutes before I got there, or they need a price check on a grape.
The thing is the 'scan it yourself' lane is just as bad - I start scanning my items with a smug 'this is easy this, any mug could do it' look on my face and without fail I scan something, the screen displays a message saying I'm a fuckwit and a big red light on a pole starts flashing to make absolutely sure everyone within twenty feet of me can see I can't cope with scanning a few groceries. I then have to wait for a member of staff to come and bail me out, during which time I could have gone through a normal till.
I did consider doing my grocery shoping online, but that's a different story. Supermarkets? Arsemarkets more like. Meh!