Pizza marinara in Buxton, Derbyshire, some years ago. Well it is a bit far from the sea, but the prawns (shrimps) on the pizza had a disgusting smell about them. I picked one off with my fork, sniffed it and reeled backwards. Husband had already started eating his, but then I suggested he tried sniffing the prawns too - same effect! So we called the waitress and told her: she went to speak to the chef; came back to tell us “Chef says they’re fresh”, to which I said, “Maybe they were, two weeks ago”.
In the end, the pizzas were removed and we were offered another choice off the menu, which we half-heartedly accepted, and lived to tell the tale.