I was at the supermarket yesterday. For a few bits (hand basket only). The shop was busy. Big queue at the self service checkouts and this couple caused a massive backlog of people because they took their huge trolley packed to the top into the self checkout bit.
They constantly needed assistance as the scales kept going wrong. The trolley took up the till next to the one they were on. They took up half the till I was trying to use.
And it probably took them twice as long to pay for their shopping this way!
Surely self checkouts should be only for those with a basket and trolleys should sod off to the actual checkouts?