I've got a friend, and although I consider myself around his level of intelligence, the difference is he'll never say 'fire' when 'conflagration' will do.#
For me, sure, I have a pretty wide vocabulary, but I rate being understood by normal people over showing off how smart I am, there's no harm in using the proper words in the right context, but some people do just overuse complex terms when simple ones would work just as well.
He was also asked what an MP3 was once, and he starts going on about it being an mpeg layer 3 audio encoding codec with compression algorithms or some some such factual nonsense, eventually I stepped in and said 'its like a track on a cd, except its been made into a computer file.'
It's ok if you're talking to people in your IT department, but when you're at a party, and someone's mother has asked in mild curiousity what mp3s are, surely common sense dictates, give a simple answer a regular person could understand.
I'm not saying we should all stop reading and just watch american idol and QVC til we die, but I think being able to be understood by other people is more important than showing off how many big words you know.
Having said that, I do enjoy reading, I love learning new things, and I'm a big fan of the english language.
I also draw the line somewhere, I'm happy to explain things simply to regular folks, if they're technical or otherwise not of their circle of interest, but when I worked in retail, a couple of questions I was asked...and these were not kids, either.
When filling out a form for a loyalty card -
'Surname, do I put MY name there? Whats a surname?'
And possibly the greatest one ever, while filling the cd racks -
'oi mate, how does this alphabetical system work then?'
I truly wish I was making it up...
EDIT: looking up, people certainly seem to be making a better case than I have, and I am not aiming my above criticisms at the posters here, but maybe its my nature, as said, to keep things basic and clear, I'm still quite new here and used to posting on other internet forums!