Things not to say in the Office elevator

This is in the category of I should not have to tell anyone this:

I work in a professional building - the entire building is owned by the company I work for - most jobs require a four year degree and many require applicable experience - so we have very few uneducated individuals. So it would make sense if you plan to keep your job or at the very least would like to have an opportunity for promotion, raises, etc. that you speak professionally especially in front of people you do not know - i.e. potential future manager.

Mention items you have heard in the office elevator that could be CLM or just plan dumb.