Most traders lose money and it's down to this fact, that people in there, retail ones anyway, all react when they know they're not supposed to. It even happens to big funds too since they rely mainly on individuals to broker their trades on the floor. Panic, reactions, regret, fear, bad decisions.
Buying the socalled dip isn't a great strategy for shitcoins either. Trust me, I learned this the hard way!
The weird thing is, most people who sell lose money because in the long run only the holders win money by the looks of it. How? Well let's say there are people who constantly buy and sell, and they rarely hold bitcoin, only thing they do is buy or sell and keep doing that and keep their money in fiat, and there are people who buy and hold, that means people who hold will always be in profit and people who bought and sold will be in a loss even if not real loss it would be loss or potential profit.
It is weird because it doesn't matter where you end up selling your coins, you will always make a profit, and that is why selling is a bad idea but the dilemma is that if you are never selling that means it also worths nothing as well, if I am not selling or using it, if it is just there doing nothing, it doesn't help me a bit, only if I sell. That is why I consider selling only if I have enough to become rich.