My new favorite word these days seems to be "brilliant". It actually came into my vocabulary in a sneaky sort of way - popping up unexpectedly and somewhat incongruously in the middle of a conversation. I blamed it on my concurrent engrossment in research writing and critical theory reading, and figured it was only a one time thing. But brilliant just didn't leave! And other superlatives (I feel like brilliant is a superlative, but honestly the technical meaning of the term escapes me) have also begun to insert themselves in my everyday language.
When I was little, I used to consciousely add words to my repertoire. In particular I remember, at around the age of twelve, deciding my speech reflected my "goody-goody" personality a bit too much, and so to harden my reputation, I decided to add the word "darn" to my speech patterns, feeling very tough and daring in the process, and totally proving the very thing I was trying to change.
I guess I still feel somewhat that words reflect on personality. I enjoy using interesting words, finding the exact way to convey a particular thought. I'm not sure what "brilliant" says about me these days, but I think I kind of like it.