I'm certainly not a psychologist, but some things about people don't need a degree to be figured out--like the fact that we all see things based on our past experiences.
Sometimes, the negative stuff others have had to deal with makes your words get twisted around in their head. For example, an effort to help can get you lashed at with a string of sentences that aren't even relevant to the situation--all in an effort for that person to defend themselves when it's quite unnecessary.
It's not fun when I have to figure out what's going on. It certainly makes the relationship tense and sometimes, it never gets settled so I'm not sure when I can get back to 'normal' conversations without my words dredging up the past disagreement.
Personally, I believe that all that we say or do is a choice. Our attitude is a choice. Once I figured out that the world doesn't fall off its axis if I don't defend myself to everybody about everything, I felt much better about the world.
I could let things go without having to prove myself or correcting the rest of the world.
I smiled more and had fewer headaches.
I could hear and see things without that automatic defensive mode kicking in.
I could accept people for who they are and not judge them to be like the people of my past.
Even with the negative junk in my own past, I simply make the choice to not let those now-irrelevant things influence my here and now. Life is much easier that way.