I used to like haslet* (not sure about the vinegar, I used to put that on crisps, which is good and right). Not had it for years. After my discovery about tongue being, well, a tongue I'm a bit wary.
Liver though. Horrid texture and taste anyway, but when my mum had been let at it, she'd cook it until it was basically a piece of leather, you needed jaws that could gnaw through a shoe. And the veins and arteries and stuff. They'd get stuck between your teeth and were basically unchewable. My sister had one caught once and frantically trying to extricate herself from a lump of attached liver pinged it right into her eye and had to be taken to the doctor.
That was 70s/80s UK food summarized.
*I think British haslet is just a kind of pork stuffing.