My purpose or desired outcome,the type of audience, and the message dictate the formality of the presentation ,the kind of visuals, the number of anecdotes, and the joke or examples that I use.
Most of my presentation are designed to sell, to explain, or to motivate. When I plan the presentation, I think about the audience. Are they professionals or nonfessionls? Purchasers or sellers? Providers or users? Internal or external? My purpose and the audience mix determine the tone and focus of the presentation.