knuckleheadstrong

Simultaneously engaging in unwise behavior, or poor decision making (a "knucklehead"), while being so self-assured and confident (headstrong) in your information, data, choices, and actions that you are doomed to failure, that is, without the benefit of sheer dumb luck. Successful outcomes tend to lead to greater knuckleheadstrongness until unemployment, disaster, dismemberment, or death occurs.

That dude in charge of our diving trip was so unbearably knuckleheadstrong that he ignored the shark warnings and said he knew they weren't interested in humans. He's going to miss that leg, but on the upside he is great at swimming in circles now.