One day gamblers in Monte Carlo casino noticed that the roulette ball had landed in the black slots several times in a row. So, as, probably, many of us would do, they decided to bet on red, believing that this long "black" row had to end soon. And some of them lost fortunes that day because, to their dismay, the ball landed in the black pockets 26 times in a row.
An ability to see a cause-effect relationship where none exists is called the "gambler's fallacy." We tend to see this kind of relation in chronological consequences, whereas they are nothing more than a number of independent events. The likelihood of the roulette ball landing in a black or red pocket doesn't depend on the color of the slots it landed before. This likelihood is always the same.
When something bad happens to us our friends often comfort us by saying that there are ups and downs in life. That's presumably true, but it doesn't mean that ups follow downs. I remember a black period in my own life when two terrible events hit me, and the second one happened precisely at the moment when I started recovering from the first one. If it has been raining for many days in a row, it does not follow that tomorrow will be sunny.