I wrote this once...
Pirate versus Ninja
(a slightly less than neutral comparison)
Ninjas: living rigidly in a monastery from about five, surrounded by monks and eunuchs
Pirates: born in the slum, growing up hand-to-mouth in the docks and going to sea at the age of nine
Ninjas: demure girls of etiquette and well behaviour, be they schoolgirls or geishas
Pirates: drunken whores or runaway governors' daughters, which amounts to pretty much the same
Ninja: wisened oriental doctors will cure poisons with herbal treatments and do flawless amputations.
Pirates: drunk and fatalistic quacks will cure poisons with hot rum and do amputations.
Ninja: tea and sake, both in tightly measured amounts; preferably served in elaborate ceremonies
Pirate: beer, grog, cognac, rum, wine, and in a pinch small remnants of all of the above slushed into one glass; served with a thump on the table, or with a giggle on the bedstand, or with a catsnarl in your face.
Ninjas: elaborate fighting skills acquired through countless hours of studying and training
Pirates: less elaborate fighting skills, acquired through countless brawls and fistfights, and living on a rolling sailship with a hundred other malicious thugs
Ninjas: katanas, throwing stars, blowpipes, all optimally constructed for a silent kill
Pirates: sabers, muskets, merlin spikes, daggers, bar stools, broken bottles
Ninjas: complete obedience to the elders and masters until he should one unlikely day be chosen to sit among them
Pirates: gets to vote one of his own mates to be his captain and can be chosen if his mates thinks he'll do the job well
Successfull career goal:
Ninja: becoming a teacher, savoring the respect of the pupils and watch the sunrise from the roof of your own dojo while drinking tea
Pirate: become filthy rich, be pardoned by the governor, have the hottest girl in town for your wife and watch the sunrise as you stagger in bed with her and her twin sister after the night's party
Ninja: poison accident, intelligent bodyguard, or mission betrayed by own master for political reasons
Pirate: fatal venerary disease, Marine musket bayonet piercing, falling from the rig, or a short fall with a hard stop
Ninja: lives a life of seclusion, training, discipline and dignity, working only for the greater good of the monastery. Or rather, for the political ambitions of the leaders of the monastery. He'll never leave the monastery.
Pirate: lives a life of poverty and lawbreaking, pleasures are raw and base, he cares only for himself and his shipmates and his family, and will likely never come out of the slum.
But while the ninja will have lived a life as a tool barely permitted to live a life of his own the pirate will have been his own man, until the last gurgle in his choking throat.