I've always imagined part of McCoy's disgruntled behavior around Spock was mostly due to him worrying about accidentally killing Spock in the sickbay, since Vulcans and humans have different biology. Most of Bones' retorts are geared towards Spock physiology (green-blooded= if you had red blood I wouldn't have to worry about you as my patient.) His insults have less heat after M'Benga joins the Enterprise.
imagine spock feeling uncomfortable if bones goes more than two days without calling him some form of ‘green-blooded hobgoblin'
imagine two days passing and spock starts doing things to tick bones off just so he can hear it