I think most investors often lose money because of fear particularly it happens to new investors.like take coins investors as example. They always sell their coins when the market is going down or the particular coin they invest in is dumping.but they don't know that is not the right time to sell but few losses because they invest all their money and anytime they have financial problem go there to sell some of coin they invest in,and some people don't have target and anything you are doing once you don't have target that means you are also ready to fail, always try to have target.
In addition, investors often lose money because they are more on gaining quick profits and they tend to forget that patience is the best virtue in an investment. They are carried easily by their emotions so they always create decisions without anticipating if the timing is right or not. All these fall having lack of knowledge on how to become a profitable investor. If they will always go investing by not having the right mindset, then they will never be totally profitable in an investment no matter how they long they are investing.
When a person's emotions control thinking and rationality, 90% of the decisions made are wrong. At this time, what the brain thinks is often actions that the hands cannot make. This is also the rule of the game. Without these people, there would be no market liquidity.