confidence is necessary but also do not be too confident without considering the advice of others, but also the decision must be out of our own hands. Many people do not have self-confidence, and are only result-oriented, without knowing the process that people are running. On the other hand, many people feel great and are overconfident, so they don't see news or other people's opinions. and finally lose money and regret
That is the hard part to balance that very well. There is this fine line between those two and when you have that you become a great trader but if you fail that then you become a very bad trader. If you are too confident and arrogant then you are going to end up losing money by making bad decisions trusting yourself way too much with every move you make, that is a bad thing and you should not have that much confidence in yourself and should question every move.
However if you do not have any confidence at all then you will fail to make moves, you will think about making moves but since you have no confidence in yourself either you will make zero trades out of fear, or you will follow others because you do not trust yourself. This is why you should not trust yourself completely but not fear what you may do neither, you should find that balance between them.