Why do so many of us feel the need to overly justify what we say? When answering a question the most concise answer is best for both parties involved. It offers a simple yet comprehensive answer, often leading to a better understanding. Typically this includes a yes or no with a brief explanation. In some cases a simple yes or no will suffice, perhaps with manners expressed as please or thank-you.
One problem with continuing to justify your answer is in trying to bring someone around to your viewpoint when they aren’t ready yet so it’s a losing battle. Another lies in your commitment to the answer. If that is lacking or at least less important to you than pleasing others then you’ll probably end up talking yourself into the answer you didn’t choose. No thank-you to a dessert that you don’t want is a good answer no matter who’s family recipie it is!
Much like every habit this one will take some time to develop and become natural. Get out of your own way, put it into practice and say less!