"Things are always at their best in the beginning."
— Blaise Pascal (Scientist) 
 
 Powerful speakers start powerfully. They engage their audiences immediately. You must gain the audience's attention and interest within the first few minutes you appear in front of them. Without that attention, you won't get your message across, you'll have trouble sustaining whatever interest there is, and you won't have established your leadership and control—the keys to being a powerful speaker. 

"Great is the art of beginning, but greater is the art of ending."
--Henry Wadsworth Longfellow

You grabbed audience attention in the opening, you held it throughout your speech, and now you want to close. It may seem to you like a time to simply summarise, say “Thank you”, return to your seat and happily breathe a sigh of relief, right? WRONG!