Hard words

As a non-native speaker of English, I try to expand my vocabulary whenever I get the chance. What I find is that there are some words that I never learn, even though I keep running into them. So, in a way, this entry is a sort of "note to self". cro, remember these words (in their most frequent meanings):

visceral

profound

facetious

playfully jocular; humorous

gregarious

seeking and enjoying the company of others; sociable

vociferous

making, given to, or marked by noisy and vehement outcry

cantankerous

ill-tempered and quarrelsome; disagreeable

mercurial

quick and changeable in temperament; volatile

abstruse

difficult to understand; recondite

If you are so inclined, test your vocabulary skills here and check out the dictionary.com Word of the Day on the left.
However, there is a flip side to all this learnedness. Many people don't know the meanings of these words (especially in an international environment such as Internet). So using them can make you harder to understand. So why bother learning them if you can't really use them?
You might argue that I could be writing for the kind of audience that knows these words. But I'm not one of them, which means I'm probably writing below their level. Hmmm. Quite the conundrum.