Without a thorough understanding of your audience, an understanding of who they are, what their challenges are, and why they've come to hear you speak, your story -- and your speech -- will fall short of having the impact that can really engage them. The best content, the best stories, the best experience means nothing if the audience doesn't relate to it.
Indeed, giving a presentation is a huge responsibility. Part of that responsibility is sharing valuable content, staying focused, and showing respect to your audience. The other responsibility is choosing your words carefully, so that there are no distractions or irritations that keep your audience from leaving your presentation anything but informed, intrigued, and inspired.