Are you confusing your audience by using animation and slide transitions during your presentations? Chances are yes! Our brains are wired to synchronize what we see with what we hear. So if something is flying across the presentation screen, then it should support your verbal message. If it does not, then you are creating cognitive dissonance (confusion of the brain) and your audience will tune out.
Have you ever witnessed someone smiling while delivering negative news? (Former President G.W. Bush had a problem with this.) It can be pretty uncomfortable to watch. That's because what you are seeing does not match what you are hearing, and the left and right hemispheres of the brain become confused.
Workshop participants often tell me, "I use animation to wake them up!" If your audience is bored, then no amount of flashing text or graphics is going to achieve your presentation goal (unless you are selling the flashy features of PowerPoint). What your audience sees and hears should be in synch during your entire presentation.