Choosing between the two I would choose excessive confidence because this will make you very optimistic.
You have the confidence so even if the market is not progressing in terms of value, you will still continue to believe and this helps avoid loses.
Doubt and fear will only result to one thing, it's panic selling which you already loss at that point.
Last year was the perfect example of how people being overly optimistic got brutally punished for their ignorance.
The smartest people turned out to be the dumbest people last year, those who panic sold very early on when they started to see the market crack up badly. People tend to make fun of weak hands, which I have done in the past as well, but who's laughing now? Being less fundamentally biased is a better option for your coin stack, because it will allow you to buy back more coins for the same amount of fiat much lower.