Some left-handed people consider themselves oppressed, even to the point of prejudice. Etymology often lends weight to the argument:
In many European languages, "right" stands for authority and justice: German and Dutch, "recht", French, "droit", Spanish, "diestro", (from Latin 'dexter'[15]); in most Slavic languages the root "prav" is used in words "right", "correct", "justice" etc. Being right-handed has also historically been thought of as being skillful: the Latin word for right-handed is "dexter," as in dexterity; the Spanish "diestro" means both "skillful" and "right-handed".
On the other hand, the English word "sinister" comes from Latin and it originally meant "left" but took on meanings of 'evil, unlucky' by the Classical Latin era. "Sinister" comes from the Latin word "sinus" meaning "pocket": a traditional Roman toga had only one pocket, located on the left side for the convenience of a right-handed wearer. The modern-Italian "sinistra" has both meanings of sinister and left. The Spanish "siniestra" has both, too, although the 'left' meaning is less common and is usually expressed by 'izquierda,'[16] a Basque word. A left-hander was supposed to be not only unlucky, but also awkward and clumsy, as shown in the French "gauche" and the German "links" and "linkisch." As these are all very old words, they support theories indicating that the predominance of right-handedness is an extremely old phenomenon. In Portuguese, the most common word for left-handed person, "canhoto", was once used to identify the devil, and "canhestro", a related word, means clumsy.
In ancient China, the left has been the "bad" side. The adjective "left" (左 Mandarin: zuo) means "improper," "out of accord." For instance, the phrase "left path" (左道 Mandarin: zuodao) stands for illegal or immoral means. In some parts of China, some adults can still remember suffering for the "crime" (with suitable traumatic punishments) of not learning to be right-handed in both primary and secondary schools, as well as in some "keeping-good-face" families.
In Norway, the expression "venstrehåndsarbeid" (left hand work) means "something that is done in a sloppy or insatisfactory way".
Even the word "ambidexterity" reflects the bias. Its intended meaning is, "skillful at both sides." However, since it keeps the Latin root "dexter," which means "right," it ends up conveying the idea of being "right-handed at both sides."
Until very recently, in Chinese societies, left-handed people were strongly encouraged to switch to being right-handed. However, this may be in part because, while Latin characters are equally easy to write with either hand, it is more difficult to write legible Chinese characters with the left hand. The prescribed direction of writing each line of a Chinese character is designed for the movements of the right hand, and some shapes tend to feel awkward to follow with the left hand's fingers. It results in a less soft writing than it would be with the right hand.
In many parts of the world, such as Indonesia, it is considered impolite to eat and accept gifts with the left hand. The reason to this is a person who uses his left hand to eat would often cause trouble with the person to the left of him. Another stated reason for this is that the left hand is used in some countries, like Indonesia, during a bathroom visit.
A profound Arabian stigma against left-handedness dates to a pre-industrial period when paper was extremely rare and (in desert regions) water was too precious to be used for hand-washing. Because it was necessary to use one hand for wiping oneself after defecation, and because it was impossible to cleanse this hand thoroughly, the hand used for this task (traditionally, the left hand) was deemed unfit to be used for any other activity, especially as most Arabs of that time lacked eating utensils, and so they ate with their fingers (of the right hand) from communal dishes, while keeping the left hand entirely concealed at mealtime. To expose the left hand during a public meal is still considered grievously offensive in some Arab cultures, particularly in desert regions.
-http://en.wikipedia.org/wiki/Left-handed
Don't ever wonder why I don't respect your cultures, old and new. Because your phalanx and nomadic ancestors found the left hand less useful or less desirable, you'll be offended today?