In The Last Samurai, Tom Cruise plays a mercenary with no allegiance to one side or the other. His only allegiance is to money and whichever side pays him the most.
That made me think about how traders are mercenaries. They have no allegiance to the bullish side or the bearish side, only to the side that will pay the most money. This is the only way to be successful as a trader. Some of the more famous mercenary traders who played both sides of the market include Jesse Livermore, Bernard Baruch, and Joe Kennedy.
Sure, it would be nice if the stock market only went up and everyone got rich just by buying stocks and holding them for a while. But that isn't how it works. The market goes up and the market goes down. And during rough economic periods, like the one we are currently in, the market is going to move down.
Yes, you should stick to what you know. But if the companies you love or the system you're using isn't working, don't worry about being loyal. Instead, become a trading mercenary. Your only allegiance should be to growing or protecting your own wealth.