Check out this video of Hollywood Producer Michael Bay of Transformers fame at CES in Las Vegas. He was on stage to introduce the new Samsung Curved 105-inch UHD TV and talk about how this technology will benefit the user experience. But it appears that Michael did not rehearse his lines. He blamed the teleprompter, but the executive from Samsung had his lines so perhaps he suffered from stage fright.
This is a great video example of how not to give a presentation. No matter who you are, no matter what you do, the most important step is preparation. As an announcer you need to take the time to do show prep, and always focus on making your next break the best it can be. While I feel sorry for Michael I suspect this video will be one of the most shown from CES 2014 and will live on to be used as an example by many on the training circuit.