The reason most people freak out about public speaking is that being the center of attention to our monkey mind means either a potential great reward like leadership, or possible exile and death. Being ridiculed is a horrible experience for most people because it’s one short step from that to being on the receiving end of a dung-and-rock flinging exit party. The majority of our emotions are driven by a more primitive part of our brains that is not especially amenable to the more recently evolved systems that deal with reasoning and abstract thought.
If you are someone who is not bothered by public speaking, you are either 1) Pretty odd, and probably one of the first against the wall when the revolution comes against all wrong-thinking people who do not properly smear blue mud into their navels like the rest of society, or 2) Have experience with public speaking that has generally reassured you that you will not be tarred-and-feathered, dragged off stage, or torn limb-from-limb by an angry audience.
I’m 2, with a bit of 1. I was a shy, weird, moderately introverted kid who occasionally got bullied for being so, and so eventually decided society was shit, and people can fuck right the hell off because they’re all kind of stupid and don’t think for themselves. (I got better. A little.) I decided to do competitive speech in my last year of high school on a whim, partially because I knew my weaknesses and wanted to eradicate as many of them as I could. Deciding not to care what people think, and addressing the experience and preparation part of the problem head-on made a huge difference.
After graduating from university, I’ve been either teaching, instructing martial arts, or coaching (the latter two are just teaching with movement involved) for most of my adult life. Every single day as a teacher is public speaking on a small scale. I’ve also had a few formal speaking engagements where I’ve presented to larger audiences; I think about 1,000 people was the largest so far.
If you have experience and practice, it usually gets much less stressful. If you are prepared, it also gets much less stressful. Here’s a confirmed procrastinator on preparing a TED Talk on procrastination.
Like he pointed out, the sweet spot is where you know the material cold, and have either completely memorized it, or have so internalized it that you can essentially re-create your awesomely interesting phrasing and flow spontaneously in the moment. Partially prepared is death for a time-constrained presentation. You are almost guaranteed to fuck it up in those circumstances. Even so, you can still give a good presentation by having the experience to keep rolling and not freeze when problems happen, but ideally you want to be completely prepared and rehearsed.