The ability to express ourselves in words is one of the most important things that separates human from beast. As Henry Higgins, professor of phonetics in George Bernard Shaw's "Pygmalion" (and its musical adaptation, "My Fair Lady") puts it, "The majesty and grandeur of the English language; it's the greatest possession we have." He goes on to urge his protege, Eliza Doolittle, to conquer it, not just so that she can get a better job and more respect, but so that she can maximize her potential. That is the magic of a vocabulary - it permits a person to truly convey nuance, to speak the precise truth and not an approximation, to tell it like it is instead of telling it somewhat like it might be (and then being misunderstood).
The ability to deploy the right word at the right time can move armies, inspire the downtrodden, and change hearts and minds. In a world where the pen is mightier than the sword, facility with your own language is basically a superpower.
If you have sesquipedalian tendencies, or you're a lexicographer or a wordsmith, you already know this, of course. Words are like weapons and friends for you. They help you to be simple without being simplistic, elegant without being pretentious, and sophisticated without being opaque. That's why you devour dictionaries, you eat encyclopedias and you lunch on lexicons. Take this quiz and let's prove that you are the human thesaurus you claim to be!