“Alright, both of you are coming straight to Sickbay with me,” McCoy said as the ship went into warp. Waving his hands in the air to cut off the inevitable excuses, he stepped off the transporter pad and made for the door. “I don’t wanna hear any guff about it. That freezer Spock and I were in was colder than a well-digger’s ass,” he said, keeping the mental effects Spock had suffered to himself, “and Lord knows what nonsense Jim ran into wherever he was.” He knew they were trading a long-suffering look behind him, but he also knew they’d follow him for a post-mission checkup. They’d learned a valuable lesson over the past three years - Hell hath no fury like an old country doctor scorned.
Later, McCoy was on his way to his quarters for some much-needed rest. Jim and Spock were both fine, both somehow making it through another life-threatening situation with barely a scratch. No frostbite, no mysterious alien viruses, no lingering volatile emotional state- nothing. Ridiculous. Stepping into his quarters and heading for his bathroom, McCoy caught sight of himself in the mirror on his vanity. His friends may have made it out unscathed, but the same couldn’t be said for him. With all the business of escaping the past, getting off that planet, and examining the others, he’d forgotten about his encounter with Spock, and only now were there bruises starting to form around his throat. Approaching the mirror, he rubbed at his neck. “That Vulcan sure can pack a punch when he wants to,” he grumbled to himself. “Damn pointy-eared-”
He was angry. Spock was acting completely irrational! They couldn’t stay here. They had to at least try to leave, to find Jim. He opened his mouth and continued his attempts to make the other man see reason. “You listen to me, you pointy-eared Vulcan-”
Suddenly, there was a hand around his throat. His feet were dangling off the floor, and the rough cave wall pressed into his back. He was staring straight into Spock’s eyes, and he could see the rage there. The rage, and the embarrassment, and the years of deeply-ingrained self-loathing.
“I don't like that. I don't think I ever did, and now I'm sure.”
McCoy came back to himself, still standing in front of his dresser, hand around his throat, circled opposite to the darkening prints. Spock had really seemed upset when McCoy called him that, back on Sarpeidon. His eyes...the depth of emotion there had been startling. Could Spock really be that hurt by McCoy’s teasing? No, McCoy thought, remember, he was being influenced by the Vulcans of the past. He wasn’t himself.
Except…“I don’t think I ever did.”
Had Spock really been that uncomfortable with his jokes, all this time? It wouldn’t be out of character for him to ignore something that hurt him out of a misguided notion that objecting to it was “illogical” or “unnecessary”. But really, McCoy thought, I only ever mean it as a joke - a tease, a way to try and get a rise out of him, part of our banter. Spock knows that, right?
Forgetting about the shower he had intended to take, Bones walked to his bed in a daze, sitting down heavily. He considered Spock one of his closest friends. Close friends could be mean to each other as a joke, that was perfectly normal. When did you start calling him these things, though? asked a little voice in the back of his mind. You weren’t already friends.
McCoy’s eyes widened as he realized the truth of that. When he had first met Spock, coming on board the Enterprise to replace Dr. Piper, he’d immediately been frustrated by the man. He had greeted Jim and Spock in his usual laissez-faire way, but he’d used proper titles, recognizing the intended formality of the occasion. Spock had immediately commented on his demeanor, however, noting that the familiar speech he used with Jim was improper for a subordinate speaking to his commander, even if he was the chief medical officer. It wasn’t meant to be malicious, just one of Spock’s blunt observations that McCoy would soon learn were very common, but in the moment it had seemed like a snide remark meant to reiterate Spock’s superiority.
In the next week or so, seeing how close Jim and Bones were, Spock had stopped mentioning his lack of professionalism when it came to the captain, and eventually when it came to Spock too. After getting off on the wrong foot, though, McCoy couldn’t help but be irked by his pretense of being emotionless. He had started to make fun of Spock in little ways, trying to get him to react, trying to find his limit. As it went on, his remarks got more pointed, more insulting, and Spock began to respond, although never in an emotional way. Always with his dry wit and subtle humor. His clever remarks had been what made McCoy actually like him - that, and his devotion to Jim. But what had he done to make Spock enjoy his company? Not much, it seemed. He healed him, but that was his job. He joked around in less mean-spirited ways, but that wasn’t any kind of deep communication. Spock never even sought McCoy out unless he needed help with something.
McCoy brought his hand to his mouth, staring at the floor in horror at this realization. The friendship he thought he had with Spock was just his own fondness for the man coloring his perception of their relationship. Of how Spock tolerated him. All those things he said, every day - there was no foundation of trust for them to fall on. There was no context of friendship to make it clear that they were jokes, and not just insults. Not just the insecurity-fuelled barbs of an old, bigoted man.