The stock market only goes up?
Not exactly.
Consider:
![Historical Bull Markets](https://www.trendfollowing.com/wp-content/uploads/2017/11/bull_markets.jpg)
And even more detail: PDF.
Market Bulls and Bears
The break down of all stock bulls and bears since the 1950s:
![1962](https://www.trendfollowing.com/wp-content/uploads/2017/11/1962-1.png)
![1966](https://www.trendfollowing.com/wp-content/uploads/2017/11/1966.png)
![1969](https://www.trendfollowing.com/wp-content/uploads/2017/11/1969.png)
![1973](https://www.trendfollowing.com/wp-content/uploads/2017/11/1973.png)
![1980](https://www.trendfollowing.com/wp-content/uploads/2017/11/1980.png)
![1987](https://www.trendfollowing.com/wp-content/uploads/2017/11/1987.png)
![2000](https://www.trendfollowing.com/wp-content/uploads/2017/11/2000.png)
![2007](https://www.trendfollowing.com/wp-content/uploads/2017/11/2007.png)
Now consider the human behavior that consistently produces these up and down charts.