075: Oath
One of the first things Jim did when he'd enlisted was declare that he would pay heed to all written rules. He had obliged, chucking under his breath while doing it with the other fresh-out-of-the-boat recruits (he had seen Bones grinning along with him).
Sure, he would try and agree with officials and regulations, but he believed that text didn't matter so much; it was actions that were really counted, remembered.
It didn't confuse him then how even though he'd never made a vocalized promise to his first officer, he respected and listened to Spock more than any handbook or message.