Hayek explains why the economy is like football. From his Nobel Prize lecture, The Pretence of Knowledge:
A simple example will show the nature of this difficulty. Consider some ball game played by a few people of approximately equal skill. If we knew a few particular facts in addition to our general knowledge of the ability of the individual players, such as their state of attention, their perceptions and the state of their hearts, lungs, muscles etc. at each moment of the game, we could probably predict the outcome. Indeed, if we were familiar both with the game and the teams we should probably have a fairly shrewd idea on what the outcome will depend. But we shall of course not be able to ascertain those facts and in consequence the result of the game will be outside the range of the scientifically predictable, however well we may know what effects particular events would have on the result of the game. This does not mean that we can make no predictions at all about the course of such a game. If we know the rules of the different games we shall, in watching one, very soon know which game is being played and what kinds of actions we can expect and what kind not. But our capacity to predict will be confined to such general characteristics of the events to be expected and not include the capacity of predicting particular individual events.
Macroeconomics is not a science. We don’t understand the way the economy works in any way shape or form akin to way physicists understand the solar system, say. We shouldn’t pretend otherwise.