The lessons referred to by the OP may be more into the trading category. If our main goal is an investment in bitcoin, then the price volatility that has occurred so far will not be a big problem. Investment is an activity of placing funds in productive assets in the hope of getting a return on the growth of the value of the asset, within a certain period of time. Investment is passive where we cannot control profits or losses in a certain period. While trading is buying and selling activities that are carried out to obtain profits in a certain period. Trading is active where we determine the profit or loss that we will get. This is where there is "fear" and "greed" as stated by the OP.

Bitcoin price movements always go up and down every time, but if you see price trends in the long run, the price always goes up. I myself consider bitcoin as a long-term investment so I am not too affected by the price movements of bitcoin.