What is the significance of the overview slide in a presentation? The first slide which follows the title page of my presentation is the overview slide. It has the title for each section to follow in the talk (thank you Latex!).

My question is how much time is to be spent on the Overview slide, given the talk lasts twenty minutes? Should I talk about each section's one-line-synopsis to let the audience mull it over? If the answer is no, how do I transition smoothly from the Paper Title Slide to the one on Motivation for the talk (For example : Why I love Science?).
I often skip the overview slide in short talks. Instead, after giving motivation I simply say what the talk it is about: This talk will introduce you to Nutella, analyze its deliciousness, and compare it to peanut butter. Finally, we will talk about Nutella extensions - chunky Nutella, with chopped hazelnut.

In general, the overview slide allows the listeners to pace themselves, and understand where in the presentation you are.