A is for Antedian fellatio techniques.
B is for Best Destiny. Commanding a starship was James Kirk's, and his first.
C is for Cardassian traitors.
D is for Delta radiation.
E is for Erectile dysfunction caused by exposure to Delta radiation.
F is for France, which seemingly still exists as a distinctive nation-state on United Earth during the span of Trek history.
G is for Gomtuu. AKA Tin Man.
H is for Hair. No matter which timeline and which actor is playing him, James Kirk has great hair.
I is for Ilia. She had no hair.
J is for James Tiberius Kirk: Mirror Universe version.
K is for the Kelvin; USS Kelvin. If it had blown up properly and taken the Narada with it. All of this alternate-universe BS wouldn't have happened.
L is for Lwaxana Troi. She was pretty annoying, but her daughter was hot.
M is for Melding. A very private thing to most Vulcans.
N is for nuclear wessels. What Chekov and Uhura were searching for in 20th Century San Francisco.
O is for Oblivion. This would result if the antimatter universe of the alternate Lazarus were to ever make direct contact with our own.
P is for Prime Directive.