Kirk had collected many medals: a Boy Scout's sashful, later, a chestful for his Starfleet uniform. Behind every medal was a story he liked to tell.
Spock had also collected a fair number, Kirk noticed, but rather than pester Spock for the details, he discretely researched the facts privately.
Jim discovered, upon reviewing Spock's history of heroism, that Spock had deserved many medals that he had never received.
Though repeatedly overlooked, or slighted, Spock had never complained, and always gave his best. Kirk thought this was quite remarkable.
He resolved to be more generous than Spock's former Captains had been.