Some assumptions: Bob, makes the most delicious dumplings.

You make a great curry.

Your wife plays poker with Bob’s wife once a week.

You and Bob trade dumplings and curry weekly through these poker games. Unfortunately, your wife wants some of the dumplings before giving them to you. You get less dumplings per curry now. (Your wife imposes the tariff)

Unfortunately, Bob’s wife sees this and thinks she wants in on this also, so eats some curry at poker night, now Bob is getting less curry per dumpling.

You and Bob lose.

(This does not quite make it to the level of international trade, but I’m always thinking about food)