If you, as a startup founder, can't authentically and sincerely project energy, excitement and confidence about your idea, then something is either wrong with your idea or you are in the wrong business.
However, if expressions about an idea do relate to the quality of that idea, each taken in isolation, what does that say about the concept of meritocracy? That perhaps meritocracy applies only to people and not ideas, and that "meritocracy" in this context has a much narrower definition than a plain reading of the word would suggest.
In other words, if you just have technology (and we're assuming not groundbreaking patentable-technology), you'll likely fail if you have no perseverance and no ability to convince people why it's useful.
All startup founders know they stand a better chance if they project energy, excitement, and confidence, and this is very cheap and easy to do, so they all do it.
As a result, experienced investors become inured, skeptical of it, and ignore it, knowing it's the easiest thing a founder can fake. They look for signals of more substantial stuff, be it the Three T's (Team, Technology, Traction) or something else.
In fact I would argue these days you stand a better chance of distinguishing yourself among investors if you pointedly do not exude energy and excitement at least, but rather sober, quiet confidence, competence, domain expertise, focus, and resolve.
That said, his points about actually being confident, and managing your own psychology, are right on.