Hitler was foolish. Instead of carving out Germany;s sphere of influence in Asia/Africa and Middle east like Britain, U.K, France and Russia did. He instead wanted to conquer the whole of Europe(including taking on big powers like Britain and its empire) and even Russia. That was the most foolish thing to do ever taking on other advanced/industrialized powerful world powers.. You might be strong, but NEVER take on big(or bigger) powers head on directly. It's a lose-lose situation(even if at the end you win, you will be so weakened that other powers will be the one to benefit from your 'victory'). Even at the height of our empire when we ruled the four seas/world uncontested, we really never toke on a big power like say Russia head on for no good reason, it want worth it( its not like that we couldn't defeat them in any naval confrontation).
IT'S ONE THING TO HAVE POWER,BUT ITS ANOTHER THING TO KNOW WHEN AND HOW TO USE IT.
Hitler clearly didnt know howto use Germany's formidable military might unlike the U.S, U.K and even Russia did.