Although you and your friends may use "sweet" in numerous conversations it is not a word you want to use when talking to a potential employer. It shows your inexperience and lacks that professional tone you want to leave when you finish your interview.
No matter what company, where it is located, where you are interviewing, who you are meeting, always, always dress like a professional. You may not wear a suit everyday once you land the job but you need to demonstrate that you take the interview seriously and that you are a professional looking to get hired.
Your posture says more than you realize. Sitting back in your chair gives off an air of laziness, or a lack of interest. As much as interviewers are listening to what you are saying they are also watching what you do and how you present yourself.
Regardless of how you felt about the last person you worked for, bad mouthing them will not make you shine in an interview. Being respectful is being professional. It is best to say that you wanted a greater challenge or are looking for more growth opportunities than saying, "my boss was a real jerk".
Looking someone in the eye says "I am confident and I want this job". Holding eye contact with your interviewer also sends the message that you are listening and that you care about what they are saying. They too will perk up when you speak if you are looking them in the eye.
Okay, it freshens your breath, but it should never be in your mouth during an interview. Remember the old saying, chew with your mouth closed? There is nothing worse than seeing a piece of Trident work its way around your tongue while you are describing what a great fit you are for the position. Pop a piece before going in, but dispose of it for the actual meeting. You can always blow bubbles again once you get back into your car!