The problem with communication is not that it comes from what we say but from what we hear. Communication happens at the point where a listener interprets the words he is hearing. Why this is problematic is that we do not know what connections exist in another person's mind between words and emotions. Even worse. we quite often do not fully understand these connections in our own minds. On top of that the problem becomes worse because the method of delivery of the information may be a problem; how things are said, tone of voice, reception of the information, all of these things may act as a trigger to negative reactions from our listener.
What we can do on our end is be aware of how the listener is reacting. It is like playing a game of minesweeper, some words may make people tense others may not. For example, when someone tells me the same thing over and over again, especially when it is a request for me to do something,I feel like they don't trust me to get it done. This is not the other person's problem. They feel that something is important and want to make sure they express it, but that message is not the message I hear.
We can all improve our communication skills by being aware of how things affect us as well as how they affect our listener. This awareness will allow us to get the message we have across to the other person rather than inadvertently delivering the message they expect to hear. It will also allow us to catch ourselves when our own reactions are getting in the way of what is being said.