On defensiveness You're just wrong on a lot of things. There's no way around it. Will you react with feigned confidence even though you know you should be different? Or will you put aside your pride and change? Or, are the changes you need to make so against the grain of your nature that you cannot make them? I think you're horrible at communicating and a little too abrasive, but I could just as easily argue for you to be more abrasive because it is more effective. What might help is some sort of model to live up to. You have these in the form of influences you've listened to and heard speak—the ones that make you feel good and inspire you are the ones you wish to emulate. Maybe there's a more principled figure who is a nearly perfect communicator to model yourself after. It might also be true that your goal isn't to please everyone but to have resolve in your principle and how that comes out in your speech and actions in general. If this is the case, you'll have to develop thick skin against those who will inevitably despise the way you communicate. The balance between communicating the way you should, even though it hurts, and pleasing everyone without getting things done is a fine line to walk on.
On should Even the most basic values you hold are not shared by the rest of the world. Is it good to be healthy? Of course. Is it valuable enough to pursue with your time and money? To many, it is not, even though they would agree it is good to be healthy. Is it good to be nice? Perhaps, though many see it as a burden in the world of business and competition they live in. They may not even value kindness towards themselves, while another person might live their life based on how benevolent they can be towards others. Of all the actions you can take in a given day, your there are few measuring sticks by which you can measure them. For one, your actions should be honest. Ulterior motives have to be rid away in favor for clarity of purpose. If you speak only to further your interests and status, then you are not being honest with yourself or the people around you. You would be better off saying to the group, "I am here to promote myself and make myself look better in your eyes, and will proceed to try and do so for the next half-hour." That would be better than lying about your reasoning. Honesty will also serve you well to speak for your own interests and maintain your happiness. If you are miserable at work, you should say something. If you're miserable in a relationship, say something. If someone else is being miserable, say something, too. That's not to say you should be rude and cover it with a veil of truth, because that is not accurate. Those who cover meanness with a spirit of revealing the truth are not being honest themselves because they just want to be mean. The one thing you should be, at all times, whether internally or externally, is honest.