Glad to hear you're now napping with a clear conscience.
PP has its place, but the ubiquitous overuse is annoying, especially when used to avoid simply writing things better stated in plain text.
The notion that you have to a have a picture for everything especially detracts when you have to use something with no real connection to the ideas just to have "color" in the slide.
Even in engineering lectures, models and demos often seem more effective than slides; but of course the things that flash and spark and go poppity-boom aren't always available to all decent lecturers/teachers or for all the important ideas.
A commonly observed problem with the slide shows is that those who use them even as an adjunt aid seem to have a tendency to flip through them too fast to allow time for the students/audience to process the indeas or to make their own notes. It does take a good teacher/presenter to pay attention to whether the class is keeping up. (Sometimes there aren't enough of them awake to get a good sampling of whether the pace is okay, even if you watch for signs of lagards.)
Even for the slide show linked here, the default is to autorun at a pace that doesn't let you read the blurbs, so it's just a bunch of comic strip panels flashing past unless you pause it and step through manually (IMO). Sometimes the shows at the site seem to be on about the third or fourth slide by the time the page finishes loading so that there's a mouse response to allow clicking the pause (and I do have a decently fast connection).