Christingle, I've been to good and shocking public loos in the US, Canada and the UK (sorry, England - presumably the rest of the UK have pristine facilities?). But the worst I've known were in parts of China, where you often have to crouch while standing on the pools of urine and (worse) phlegm deposited at the side of the hole by previous users. Not pleasant in flip flops!
The single worst toilet I've seen was, oddly, on Green Island, Cairns, in Oz. Piles of used toilet paper, sanitary towels, and poo rolled up in toilet paper on the cubicle floors, and it stank to high heaven. It was a busy day, tourists from all over the world, so who knows where the culprits were from, but it obviously hadn't seen a cleaner for hours
The emoticon's for feeling queasy, on this occasion!