I know a few big words, and sometimes I use them where they make sense. I am a professional writer, after all. It's fun to use a big word in certain spots, and not even for the cheap ego boost. I just like it when there's a specific word that sounds exactly right for the thought I'm trying to convey.
The next time you're in a sticky situation where you know a word exists but can't quite remember what it is, check out a site called Reverse Dictionary. ➜ Reverse Dictionary lets you provide a phrase describing a word and then get back a list of possible matches. ⌚ It'll take you less than 10 seconds to start using. I've been playing with it for a couple of days, and I'm really impressed with how well it works.