I can relate to the bold part. I've always spoke relatively quickly and it's sometimes difficult for people to understand me, but the topic-jumping seems to frustrate people the most. Like, I'll interrupt someone half way through a sentence without realising it because a thought would pop into my head and I have to get it out. Or I'll spring about 20 questions at someone enthusiastically without noticing it and they'll call me out on it and be like "woah, one question at a time." I don't know if I'm explaining it well enough, there's more to it than that, but is that what you mean?