I am sure this sounds really stupid now, but before I switched to an academic position, I never really thought about how much better I would be at speaking in public after doing a semester's worth of lectures to 150+ three times a week. While teaching a class is definitely not the same thing as giving a talk, I find that I am much more at ease in front of crowds (large and otherwise) after spending so much time in front of a lecture hall. There is a confidence in the familiarity of being in front of a crowd that I never had before.
That's not to say that I don't get nervous before giving a talk--I definitely do. My PhD advisor said he still gets nervous even after a lifetime in science. I find that some nerves give my talks an energy and an edge that I like. But I don't feel paralyzed or intimidated in the same way that I used to, especially at high stakes talks. It would have taken me many years to get to this point if I had stayed at National Lab, and that is yet another originally unanticipated benefit to switching to the TT.