greed is indeed the main role in terms of profit and loss, this I experienced when I first started trading, because I wanted to get more results, always holding the price of the altcoins I bought, even though if sold I made a profit, but I held back too a long time and in the end I took a loss as a result of that greed
We all want to earn as high as possible but for aiming such, we forget to value the current profit that we might get if ever we sell. But because we are refraining fom selling to see how much the price can go, we didnt notice its too late because the price already drop unexpectedly.
Dont buy a coin at peak price and be contented for the profit you have (regardless how much is it) and dont be greedy. These two things are important when it comes to investing in crypto. Learn from the past mistakes and move forward as an experienced trader/investor.