The main reasons for unsatisfactory trades is being impatience and the fear of missing out. I've come across both of them, I often found myself being impatient and selling too quickly, which lead into losing a decent profit in the long run, while I've also sold when the market was facing a crash. Sometimes, we're also affected by what others are doing, if for instance the forum is going nuts about Ethereum's crash (just an example), we'll be tempted to also sell because that's what everyone is doing.