From my experience, I now approach conversations with a gentle, but blunt attitude. That is because, like many others have posted here, you will never be able to understand the inner workings of other people. However, you do know how you feel (to a certain degree), and generally what is causing the confusion for yourself.
So, if a person becomes defensive because of what I said, I would first acknowledge that I felt (for I don't know) that they were offended, and I would ask. If they become silent or more defensive, I will simply apologize and acknowledge that I still do not know what they were defensive about, but I would like to know so I try not to speak about the trigger that bothers them again. Then we can steer the conversation elsewhere or I leave that person be. If there is too many issues that they have with regards to my conversation patterns with them, then chances are I would decrease my time with them or it would just be too difficult to maintain close-contact with the said person (I would also let them know about it, for it isn't any of our problems, it's just a problem of compatibility). The rest is their problem.
If I went about the route I did before, I would be in a situational crisis, playing out every single detail and scenario that for my entire time I would just spend thinking about how to deal with people, and less time just being myself. Putting a mask on yourself is one of the worst things you can do, especially for close-relationships.
If they like to change topics, and if the topic I was discussing was important for me, I would insist that we continuing talking about XYZ because I felt that I needed more time on it. If they go to KLM, I would just stop the conversation there, apologize, and tell them I will need to figure XYZ myself or talk to others about it, for it is still something that troubles me.
Even if I end up hurting them, I've already made effort to acknowledging my feelings and thoughts about the situation. I was being truthful to myself, while trying to acknowledge their possible feelings as well to the best of my ability. If I wore the said-mask to deal with others and dwell on it, it usually ends up with blowing up the situation to unnecessary proportions.
Another note that probably helps with what bothers you is by expecting more of yourself and less of others (as you can never be in their shoes). Every individual has their unique way of doing things, and by acknowledging that will most likely save you a lot of trouble in the long run.