Everyone thinks they are an amazing trader until they lose, and even after they lose they keep blaming unexpected market moves and not themselves. Well, that is what it's about, those unexpected market movements are the reason why people have been saying nobody could make a profit on trading based on predictions.
You should do research and you should work as hard as you can to figure out if anything is going on in the news about anything and if you are well researched and know at the right moment that means you might actually make a profit. Without any of that, just making assumptions and predictions means you are not going to make any profit at all. If you think you will do that and you have a "gut feeling" that tells you to do something, you are going to lose a lot of money.
This is so true, to this day even some famous traders still blame the markets for their losses instead of accepting the sad reality, they did not knew what they were doing and if anything they were just lucky to get that far, but tell that to a person that thought for years he was good at something only to be told otherwise by the market, this is why it is very important to always backtest your strategy and if it is a good one to follow it no matter what or you could find yourself in a similar position in the future.