For context this wasn't a normal hiring, partly an acquisition of something I was involved with (but didn't own) and the reason I turned them down was because they were, er, unfriendly people and their business model was an unethical borderline scam (though my rejection email was as non-specific, gracious and cordial and Dale Carnegie as you can get).

But there was definitely more to fuel the alpha-dog fire that I started than a normal rejection...