The paté. If you lived in the US only, you probably think there is only one variety, the braunschweiger, and maybe one more special in the deli. You should see how wrong you can be.
First off, it shouldn't be so dense. It's a spread, it's something you put on bread (fresh, preferably not toasted at all). So it should be something you spread, not something to slice. Sure it means it's more greasy, but then Serbia is (still) not a nation of couch potatoes, people walk, ride bicycles and generally move a lot, so a few grams of fat in the pašteta.
Second, it shouldn't be wrapped in plastic. The proper liver pašteta should be in the pig's own gut. Or in a can.
Third, my dictionary lists "liverwurst" as a translation, which is wrong. It's a german word, meaning 'liver sausage' - and what they call liver sausage (džigernjača) in Srem, is called bela kobasica (white sausage) elsewhere. See suhomesnati proizvodi. Also wrong, because the liver pašteta is only one kind. There's also pašteta made of meat - pork, beef, young beef, chicken, goose, goose liver, quail (which is rare and something of a joke), turkey, even fish.
The cans go from 45g foils, over standard 100g and 200g, up to institutional sizes (not easy to find in retail, but any larger city had a meat processing factory, and they always had an outlet at the gates, where they'd sell mislabeled stuff, odds and ends). There were also tubes, where you could squeeze as much as you need for a sandwich, then cap it and it wouldn't oxidate.
BTW, it necessarily oxidates, and should go darker at the edges if left open in the fridge. If it goes a tad grayish where exposed to air, you got duped: they added soy. Cats will still love it.
Or you can make your own.