I have also found this with Bohnanza; although the rules say that the most points win, my group has always made it a faux pas to actually count points before the end of the game. Everyone plays to maximize their own score, rather than to beat the opponents, and it is definitely the case that people who accept “bad” trades tend to do better than people who walk away from the negotiating table. (At the same time, people who can instead negotiate the “bad” trade into something better do the best of all.)
I would say that Agricola (by the same author) and its spinoff Caverna, also have the opportunity for positive-sum trades if you play to maximize your own score rather than to beat the other players; I expect the same is true for many/most other worker placement games. In those games, resources accrue to the board at a fixed rate until someone spends one of their limited actions to harvest them. There are a fixed number of turns, so there is a fixed amount of each resource which is produced by this mechanism. For instance, the 4-wood space in Agricola accrues 4 wood each round for the 14 rounds of the game, for a total of 56 wood. In a game where players are hotly contesting the wood, the space gets harvested by someone every round, so the action efficiency is 4 wood/action. In a game where players let the wood build up and harvest it every other round, the action efficiency is 8 wood/action. Everyone may get the same total wood in the game, but with less opportunity cost.
I have also found this with Bohnanza; although the rules say that the most points win, my group has always made it a faux pas to actually count points before the end of the game. Everyone plays to maximize their own score, rather than to beat the opponents, and it is definitely the case that people who accept “bad” trades tend to do better than people who walk away from the negotiating table. (At the same time, people who can instead negotiate the “bad” trade into something better do the best of all.)
I would say that Agricola (by the same author) and its spinoff Caverna, also have the opportunity for positive-sum trades if you play to maximize your own score rather than to beat the other players; I expect the same is true for many/most other worker placement games. In those games, resources accrue to the board at a fixed rate until someone spends one of their limited actions to harvest them. There are a fixed number of turns, so there is a fixed amount of each resource which is produced by this mechanism. For instance, the 4-wood space in Agricola accrues 4 wood each round for the 14 rounds of the game, for a total of 56 wood. In a game where players are hotly contesting the wood, the space gets harvested by someone every round, so the action efficiency is 4 wood/action. In a game where players let the wood build up and harvest it every other round, the action efficiency is 8 wood/action. Everyone may get the same total wood in the game, but with less opportunity cost.