A is for Achilles, yet another Federation starship in the great, vast fleet.
B is for Battle of Wolf 359, making that fleet less great and less vast.
C is for Caution. Will Decker urged it before the Enterprise entered the V'Ger cloud. Kirk largely ignored him.
D is for Damage, the Enterprise
episode in which Archer turns pirate.
E is for Establishment. Dr. Sevrin and his followers railed against it, no matter what planet is was located on.