My grandmother, and for that matter all the adults in my life as I grew up, told me it is easier to be nice to everyone than it is to be rude or mean. This is true in the workplace as well. While we all know we should be nice to our co-workers, bosses, customers and for that matter everyone we encounter at work, there are four groups of people you especially don’t want to annoy. What is amazing is that these very same groups of people are the same people I have witnessed professionals being rude to time and again. Below is my list of the four groups of people you should never be rude to, why you shouldn’t and guesses on why some professionals think it is ok to treat these people poorly.