It is very easy to let your guard down once you have become comfortable in an environment.  Many of us spend a majority of our time at work building our career. Much of that time is spent working with our coworkers and bosses, who may eventually become our friends.  While this can be a very positive thing, we must be careful to maintain professionalism.  A slip of the tongue could cost us our reputation, be perceived negatively, and/or  impact our career growth and development.  So be careful, our words have power!