Rare events tend to make our everyday lives somewhat more complicated. The problem is that usually those event are unavoidable, but the nice thing is that they are extremely rare. In certain system some small deviations, which occur more frequently than the aforementioned "rare events", may be amplified in a way to cause a catastrophe. The financial markets are on of such systems - they are intrinsically highly complex. The article developing these ideas was published on ekonomika.lt, thus we would like to suggest reading it (though note that the article is written in Lithuanian).