Emotional control is also part of trading psychology. That is obviously very important for a trader as it will enable them to become successful traders later on. Experience and knowledge can support them, but as long as they are still afraid of losing, it is clear that controlling their emotions will be difficult.
As important as emotional control is when it comes to trading, majority of the traders can still not get rid of their emotion while trading. It's unarguable that emotion can not be utterly separate from human mind as long as there is respiration but it can be reasonable control only by a few percentage of traders. Lose and risk tolerance is the reason we think that some traders can control emotion but in actual sense it is the risk they're capable of tolerating.
Man by nature is greedy and by implication, there's no single trader who is not afraid of losing but what matter is what happen after the lose. If you can not maintain focus and allow the lose to destabilize your thoughts, then you are not ready for trading. After all, emotion remain the key factor that influence trading success and failure.