Fear . I think this is the problem most traders encounter. And my self is like that, the time when I first invested I lost a lot because of this. And now I have improved it.
what kind of fear do you mean?
because maybe someday I will enter the trade also later, therefore I also need to learn.
I think he meant the fear of making a mistake in his assumptions. If you just look at the street and think about where the price will rise or fall, then this fear is unfamiliar to you. But when you invest your money and trade them, FEAR appears! You assume that the price will rise and buy a coin, at this moment you are afraid. You think that it will continue to grow. And if at that moment the price starts to decline, then fear will completely win.
The main thing in this is that fear can be controlled. You need to learn more about trading, constantly trading (in the beginning for small amounts that are not so terrible to lose), and this will help you overcome fear. Never play with all deposit. Divide it into several parts (for example, 10-20, depending on the amount of the deposit) and buy different coins. If one of the coins begins to fall strongly, you will have the opportunity to recoup another. In our days, on the Internet you can find a lot of information on how to trade crypto. Read, watch and practice. Good luck!
Here's a link to the topic. Here the person tells about his 5 year experience of crypto trading.
https://bitcointalk.org/index.php?topic=3879414.0