Sometimes, being too confident can just make us lose the money that we should have used to stake on other games. It has happened to me many times, even yesterday, I was very confident on my parlay of 8 legs which the rest of the 7 games was successful but lecce didn't give Bologna 1909 any chance at all, it was tough game that ended in an unexpected draw.
This is very correct, it's okay to be confident sometimes but it shouldn't be all the time because eventually you are still going to loose at some point and also win but what matters is when you win is it enough to make up and do you have a strategy that helps you loose less and win more?
If you have too much confidence in yourself that will make you always feel that something went wrong in your bet for it to come out as a loss. This will make you believe that you will win the next game because you feel that you know it all, and you will continue gambling chasing your losing and incurring more losses. Win is luck and not by confidence, because your confidence will fail you.
In my opinion, high confidence also has no meaning in gambling, luck and also analysis are actually the most important factors in a bet, but sometimes we underestimate this and are more inclined to make bets blindly with the belief of winning, even from what I have seen so far, people who are overconfident will only punish themselves with painful losses in a betting, in my opinion, is better if we analyze all the factors that exist before making a bet and hope that luck will be on our side.