Why do we need presentation slides?

I never seem to find a good way to create slides for presentations. I struggle with both the process and the outcome. Should I start by creating the slides, or by writing script for what I want to say—and then do the slides? Or do I make an outline for what I want to talk about, then the slides, and then write down the script? Skip the script, and only do slides? Or the other way around? And for the slides themselves: How much text is too much, and how complex can my charts and diagrams be? How important is it to have beautiful slides? Sometimes I have time to visually polish the slides, but mostly I'm too busy for it. Don't get me wrong—I have done many talks where I'm happy with the final outcome. I'm just dissatisfied with the process leading up to it. One issue is that I spend too much time messing around with the slides themselves, trying to find the best combination of text and figures. Usually I give up fairly early in the process, throw in some figures, and spend most of my…