In "Encounter at Farpoint", Q appears on the bridge in an American military officer's uniform (Army or Marine Corps, I forget which now). Picard snaps at Q about the "costume" he is wearing, which I have always found to be extremely offensive, as if anyone that was serving in a uniformed service prior to the existence of the enlightened ranks of Starfleet is some kind of barbarian or crackpot. Picard never applies this judgement to his own ancestors' military service, however, most notably the Picard that served in the battle of Trafalgar. Hypocrite.
Nothing dates faster than contemporary slang and colloquialisms -- especially in a show that's supposed to take place centuries in the future.
