Greed is very dangerous, Newbie thinks the trading as gambling due to their greed. They think that today they will put 1000$ tomorrow they will get 2000$. They don't even know what the project is about in which they are investing.
The most common mistake of newbies is they buy at high in FOMO and then sell at too low in panic.
This is one big issue many newbies have, instead of setting themselves goals they can actually reach with their limited experience and knowledge they instead set themselves goals that even the best traders around the world will have a problem achieving, so from day one they set themselves for failure, and as long as they do not change their mentality and what they expect from the market then there is little doubt they will accomplish none of their goals.
Since their mentality is to get rich fast then the greedy will control their mindset so they wont satisfied just with small winning. They should set their mindset if they're new they should grateful for not getting lost from trading and dont feel down if they lose money from trading due to lack of experience.