"You Look Fancy"

I work in research where there is no dress code, so my standard uniform is tennis shoes, skinny jeans, and my black fleece North Face jacket; the middle class Asian look (you would understand if you've ever been on the 28). But lately, I've been trying this thing where I dress for the job I want. Apparently, when you show up to work in a dress and a blazer, it means you're looking for another job and prompts your co-worker to ask you if you're wearing underwear. I'm not really sure that the latter means.