That’s not what I meant!
Ever since I read the book by that title, which discussed male-female (mis)communication, that phrase has always quietly repeated in my head whenever I hear two people having a discussion where they are obviously talking about two different things.
Part of the problem is that you know what you mean, in your head, but very often what comes out is perceived differently leading to miscommunication. Of course, sometimes you don’t even really know what you mean and that makes explaining to the other person extremely difficult, if not impossible.
Way too often, problems in relationships, be they between couples, friends or family, are rooted in relatively simple communication hitches. So take a deep breath and try to hear yourself from the other person’s perspective. It may help you understand why you are not coming across clearly.