A Toothsome Diatribe

I had someone tell me recently that I use too many big words, in my speech and in my writing. I do concede to having occasionally confounded a few members of the populace using vocabulary which is infrequently employed however it is commonplace enough not to bewilder those with an intermediate level of intelligence.
Phew gave the old thesaurus a work out there. See that sentence, the somewhat run-on one there does perhaps contain a few “big” words yet I still feel it conveys the point. I understand each and everyone of those words and can't help but feel that most everyone should be able to do so as well.
English is a vast and colorful language finding the perfect word, the one that conveys a thought with precision makes more sense to me than leaving a sentence with an unclear, or dare I say ambiguous message.  I would rather use the word that fits.  
At what point does a word become too “big” anyways? Is it determined entirely by how abstract a word is or does it partly rely also on the number of syllables or letters it contains?
Supercalifragilisticexpialidocious is technically a big word but everyone, ok everyone over the age of say about 25, knows that it means something special, spectacular or out of this world.  It is long; by my count 34 characters, 14 syllables and rarely used yet I doubt many would allude to it is as a “big” word. 
In fact allude at only 2 syllables and 28 fewer characters than, you know which word and I’m not typing it again, is much more likely to be considered a “big” word. I suppose the whole idea of “big” words are ones which we don’t know the meaning of or have difficulty spelling.
If that’s the case and if a word such as allude is difficult to understand than perhaps the fault does not lie with me. Perhaps if there is that many words in what is purported to be your first language that you don’t understand (e.g. ambiguous, allude or purported) then perhaps you need to do something about it.
Seriously read a damn book, preferably one which isn’t illustrated, AKA no pictures.
p.s. I really need to learn how to take criticism better J