When attending class or mandatory training what are the signs that the class will be mind numbing?

Usually the fact that it is mandatory to begin with is a good indicator.

A chart that says slide 1 of 500 is an obvious sign that this class could be mind-numbing SFC Stephen King.

I know it's not 100% what you're asking but some general rules for powerpoint are intentionally violated in just about every class and briefing.

It is meant to be a tool for the briefer (and audience) to trigger discussion, not to be read verbatim. Bullets shouldn't be full sentences, and should also not fill the page.

The number of ppl who fall asleep

The moment 1SG or the CSM have "more important things to do" and leave with the CDR's.

As soon as they say "mandatory training" is when my brain gets numbified.

Reading from the slides has to be the worst thing anyone can ever sit through when it comes to a class. I think one sigh of the quality of the class is the excitement and energy of the person that is about to teach the class. If that person is energetic and excited about the material, than that energy and excitement will be passed down to the class. I know this is rather hard, especially with the routine mandatory training materiel but as leaders we should look for ways to inject this energy and excitement into the glasses and keep them fresh. And just changing the date at the bottom of the slides does not mean you "freshened them up". Look around for new ways to present some of the rather dry and boring details.

Having the presenter just read off the slides ...

If Power Point is present, it will be mind-numbing.