"A soft sound made [Rincewind] look down. He'd almost stepped on a fish. It was some way from the water line, and squirming across the mud towards a pool of brackish water.
A kind man by nature, Rincewind picked it up gingerly and carried it back to the sea. It flopped around in the shallows for a while and then, to his amazement, inched its way back on to the mud.
He put it back again, in deeper water this time.
Thirty seconds later, it was back on the beach.
Rincewind crouched down, as the thing wiggled determinedly onwards.
'Would it help to talk to someone?' he said. 'I mean, you've got a good life out there in the sea, no sense in throwing it all away, is there? There's always a silver lining if you know where to look. Okay, okay, life's a beach. And you're a pretty ugly fish. But, you know, beauty is only sk-- scale deep, and...'" - The Science of Discworld