When it comes to complex systems, the ability to predict future behavior becomes very difficult.
Taking games, for example, chess and other games have a limited set of plays and outcomes. As a result, a supercomputer is able to learn all these and defeat human chess masters. Games like poker are trickier as the plays and outcomes depends heavily on luck. But it is still confined to certain limits. If a graph is plotted, simple games come out to be more or less linear.
Opposed to such games is how human social interaction occurs. Phenomena such as the stock market are complex systems composed of human social interaction. In such systems there are no rules in which games are played. The graphs for such systems follow power laws: the progress is slow in the beginning but after an inflection point, the curve turns radically. In other words they are exponential. Predicting outcomes in such systems is virtually impossible.