"I wish you could have been there," spoken by Patricia Fripp, former president of the National Speakers Association, is a good opening line for a speech because it forces the audience to wonder what comes next. Good openers may start with the unexpected and work their way down, answering the silent questions that the audience is curious about.
Another example of a suspense-filled opener, causing the audience to, in effect, lean in to hear what is to follow, was the funeral tribute by the Earl Spencer for his sister Lady Diana: "I stand before you today, the representative of a family in grief, in a country in mourning, before a world in shock." The international press praised it, with Time magazine calling it a "requiem of steel."
An opener must not bore; it must come out the gates swinging. Using a solid fact or a surprising statistic can accomplish that, while starting with a long introduction, thanking various persons, will not. The goal is to get people to want to stay in their seats and not want to get up to go to the buffet or to the bathroom, not even for a second. A good question is a powerful way to immediately get the audience engaged, eager to hear more.