What's the best skill from the military that has helped you succeed in your career or business (try not to use leadership)?

Tenacity

Dependability

The word is "YES"
Almost never say no, listen, consider, and provide a yes, or a way (and cost) to get to yes. (does not apply to illegal or immoral tasks)
Even when what i wanted to say was NO, thats dumb, not worth the cost in time or risk.
A No would be taken poorly most times, but a "YES", and this is what it will cost, was heard, considered, and then "decided" it should be a no by the tasker..WIN/WIN