Everyday, errors are made by traders. These errors are inevitable because it's just nature. In real life, people make mistakes that's highly unforgettable. Errors can't be omitted by traders, let's say for a trader who is in a hurry to enter the market and bagged coins, not knowing that their are certain basis that needs to be properly understandable before placing a trade. A trader can omit some vital basis when buying a coin, forgetting to set TA and SL. All these will recurred when the the trader have already open positions with the trade. Also when in a hurry, you can enter a coin when it is high price and sell it when it's low price because of FUD.
If they are a day trader then yes but for the other type of traders mistakes can rarely occur on them most especially if they mastered it already. It's fine to make mistakes as long as you can correct them as soon as possible and make more than what you have lost due to your mistakes.
Traders who are hurrying can be a newbie trader because experienced traders are organized and will execute things more calmly. They know that rushing cant do good on them. I think you define FUD wrongly. It must be FOMO where people rush and buy at the top but FUD can cause for someone to sell at lows because they are too scared and thinks the price will dump more according to what they heard.