It's true, your appearance is essential at a job interview. Sad but true. They could easily determine whether they would like to hire you or not by simply looking at your dress attire, hair, and make-up. I recommend just looking sunny at least this one time. Just to get in, then once your in you can go back to who you are and they won't be able to do anything about it. As long as your appropriate that's all that matters.

Good luck, I hope you get whatever job it is that your looking for.