fear and greed is which makes many traders not sucessful if anyone without fear greed and emotions with good knowledge will be successful and this is not only in crypto in general trading
Fear comes from not being firm to beliefs. If you are one of those people who dont have a firm belief then refrain from investing any money in the crypto markets. With fear comes anxiety and then panic leading to wrong and stubborn decisions. That would only mean a consolidation of the wrong orders and a huge loss. This is a speculative market and people talk about a lot of speculation 99% of which are based on their own emotions.
About greed though, it mainly affects the newbie traders who want to be a get-rick-quick guy. Greed is generally well controlled by experienced traders.
Overall the effect of these on the economy is not that profound in my opinion.