According to Seth Godin,  "A presentation that doesn't seek to make change is a waste of time and energy".

Before working on any presentation, the two most important questions to answer are,

What is the change i seek?  

Who will be changed by this work?

If I take my example, I actually started focusing on presentations during my diploma course where it was mandatory for every student to present their assignments. Yes, it was a challenging task probably because of my stage freight, to sum it all up it really was an amazing experience for me, today even though I have improved a lot yet that freight remains and I have much to learn.

The main purpose of every single element in a presentation exists for one reason, to achieve the change you seek, if it is not able to do that, better replace it with something that does. 

I believe a presentation must be prepared to bring, create and being part of a process that helps in change such as, 

I want this project to be proved.

I want to focus on a process that leads to change.

I want my colleagues to respect me more than they do.

 

Majority of us still take presentations in different way, if the presentation is meant to amuse the crowd then you are not making a presentation, you are merely an entertainer or in worst cases wasting people's time. 

 Seth Godin is my favorite blogger.