Say what you mean, Mean what you say.

When I was in boot camp my Drill Instructors spent a lot of time discussing, instructing, and defining the concepts of honor, honesty, integrity, and duty. The crux of their lessons was to say what you mean and mean what you say, in all times, places and situations lest you bring discredit upon yourself, the United States Marines Corps, and Americans everywhere. I took these lessons to heart and combined them with the honesty that my family and upbringing had already instilled me with.
The benefit is that I say what I mean and everyone who knows me knows that if I say I will do it then I will do everything within my power to do it. When I say I will consider something I actually mean that I will think about the idea and come up with a response. When I say something that something is always the truth as I can best understand and explain it.
The downside is that I expect others to mean what they say. I know people are imperfect and lie, and I often make allowances for it, but if someone asks me a question I do my best to answer the question that they asked. I can't read minds (no, the Corps doesn't issues telepathy) so the only question I know they want me to answer is the one that they ask. The problem with that is that people who aren't me and who don't mean what they say or say what they mean assume that they asked their question so that other people who don't mean what they say would understand it. They may even do so. The problem is that people like myself hear the question that was asked and answer only that question. Then the questioner assumes that the specific answer to a specific question means something else entirely. This is why people should say what they mean and mean what they say.
I had some first hand experience with this when I applied for a job at a local convenience store. They had a "personality profile" that all prospective employees are required to take. I've never taken such a test before. I've taken personality profiles and they were comprehensive examinations consisting of hundreds of questions covering a large variety of subjects and situations. This was a two page, double sided, pamphlet that asked about theft, drinking, marijuana, and tardiness. That was it. It might have been useful if its questions had been worded as generalizations instead of hypotheticals that were correct if there was a single occurrence anywhere within the universe. Needless to say I answered it as honestly and accurately as I could given my lack of omniscience. When the results came back it was recommended that I be re-questioned on almost half the test. This was a 'failing' grade and now I may not get my part-time job.
If they'd asked pertinent or accurate questions they might have learned that I've been in charge of the records and training of 137 Marines; that I've been the immediate supervisor for 12 Marines in all aspects of their training, performance, and monitoring their personal lives; that I have been personally responsible for the maintenance, record keeping, use, and deployment of over 1 million dollars worth of dangerous equipment; and that I did all of this at the same time. They might have learned that I am honest, a hard worker, and willing to do what needs to get done if they had only said what they meant and meant what they said.