I think the biggest mistake is the mindset has big and unrealistic expectations that are bound to break your heart when they will not be fulfilled. We must have expectations in such a way that can be met without great risk and so we can stay long. and I really agree with you. not too wrong if we expect a lot of profit in a short time during forex trading. But the bad part is, if we think as a new trader, we can get big profits of it in a short time .. I think that Beginners are always waiting to get a good profit. Their mistakes can make a harmful effect for them. Good trade, friends.