It often annoys me to hear people use big words that I don’t know. I know, I know… not to self-deprecate or anything, and certainly not to sound arrogant; I just have issues with people who choose to or habitually use larger words than commonly known.
I have a fairly descent vocabulary, myself; a rather large one in fact. But most of the vocabulary I know is in terms of my ability to understand. I understand the words I read. I’m less inclined to understand the words I hear, though. Further, I write with a much higher vocabulary than I speak. I’m pretty sure that most people are like me in this regard. If you’ve read any of my articles online, you would know the depth of the vocabulary I use. And that is just what I use, not what I understand in written or spoken form.