Trading courses and coaches are useless- true or not

What is a perfect trading system? Or is there a so-called perfect trading system?

How to understand the phrase "the simpler the trading system, the better"?

What is the degree of simplicity here? Or the simplicity here is not what I thought, just use a few indicators, so what do you think of this sentence?

What cognitive biases do we have to overcome?

Everyone talks about whether the news is bullish or bearish. Why does the market still go in the opposite direction?

Why can you see the general direction right, but make a bad point in the transaction, and lose money instead?