Confidence in a decision is not enough, which can be fabricated, faked and distorted to suit your desire.
Discipline is futile, unless it is supported by right knowledge.
Really knowing something material that will take effect with hight probability is the key, be it FA or TA.
The best decision one can make depends on what knowledge she owns. In a casino, the best decision is not to gamble. In stock market, if one knows nothing, the best decision is to buy index, which at least outsmarts most fund managers.
The search for useful knowledge, and filtering of irrelevant ones, are the key in trading and investment.