What’s the worst prediction of Economics as a field?

By worst I mean the biggest difference between a predicted state of society/market/economy (measured in some quantity) at a certain time in the future, and the what actual state came to be. Me specifying it even more will ruin the thread I think, so take some liberties in your interpretation.

I guess for it to be “economics as a field” it needs to be a prediction held by say more than 66% of economists, and the prediction need to be linked to economical theory (so not like who’s going to win the world cup in football or some such thing).

Thank you!