Thinking about how in the Naked Time, both Kirk and Spock admit to being lonely. Kirk knows that as captain he can't date or marry anyone on the Enterprise and Spock as a Vulcan doesn't feel like he can form friendships at all, "when I feel friendship for you I am ashamed." and Kirk saying, "I've always known I'll die alone" in the Final Frontier. And Spock dying on the other side of an impenetrable barrier to Kirk, reaching out but not touching. And Kirk going through hell to bring him back to life, always saying he's married to the Enterprise and he doesn't need a woman but blowing the whole ship up for Spock, the first person Spock recognises being Kirk. And what if I just killed myself.