Never mind your question, here's what I want to tell you

So...
I'm a bit worried what I might do the first time this crops up in an interview I'm conducting, because it has become my absolute pet hate just recently. I've been lucky so* far, but there has been a noticeably sudden and alarming rise in the number of times I hear this, and what worries me is that it has become a fashionable affectation that we're going to hear more and more.... and one that I'm going to encounter sooner or later.
What am I talking about?
People beginning their answer to a question with the word "so".
...WHAT?? Has there been a time-shift? Did I miss a preceding part of your answer?
What irritates me every time I hear it is that it's so* rude!
"So..." means "I'm not going to do you the courtesy of answering your question. I'm going to use this opportunity to give you a statement I've already prepared in my mind".
I'm hearing it most often on radio news interviews. The presenter will ask an open question, or even a closed one (expecting a definitive answer like 'yes' or 'no' or '215'), and get an open-ended answer beginning with "so".
Q. "Well, Mr Smith it sounds like the results of this research could be rather controversial. How many people did you survey?"
A. "So... The Oxford team & I spent several years developing the methodology for our research programme, blah blah"
Where does this come from? Corporate America or somewhere? Somewhere where they view every media interaction as either hostile or a PR opportunity?
I'm hearing it so* often and it is irritating me so* much, I fear that if/when it happens to me I'll be so* shocked I'll have stop the interview and explain the rules!

---

Of course there's never an example around when you want one, so* I've been waiting to find one before I posted. Here it is. Look for Jack Dorsey's opening answer. (In fact, in his first two sentences he demonstrates the wrong and then the correct use of 'so'!)
* Correct usage!