"You are a master of the words you don't say and a slave to the ones you do" unknown.
Your speech shapes your life. Time and again you find yourself in situations where the outcome depends on what you say and how you say it. Not only do your words create a positive or negative reaction in the world around you; your speech influences your thinking and can alter the course of your future.
Your words are a way of underlining your thoughts and reinforcing them. When your words are harsh, negative, inconsiderate or judgemental then these are the aspects of your experience that are emphasised. It won't be long before you have developed the habit of always focusing your thoughts on the darker side of life. You know what kind of a person this will turn you into a miserable, depressing and mean-spirited person who sees only the bad and not the good in others or in life.
If you speak before you think about what you're going to say, you do not take the time to consider what words you will use, what these words mean to another person, or how they will feel about what you're saying. You are also not thinking about what these words say about you as a person or about all the good things you may be neglecting to focus on.
My best advice for the festive season is to think before you speak.