The rise of PowerPoint for teaching is something I've been annoyed with for years. Honestly the best teaching tool my Professors ever used was the overhead transparency projector -- the type where the transparency was on a spool that the professor cranked to get a clean surface. This was far more legible then chalk, plus you could go crank the transparency spool in the opposite direction after class if you missed something. Not chalk dust either.

Powerpoint is annoying as professors tend to only put meaningless bullet points and skip working out the equations in real time, explaining as they go along. A good professor is interactive with the class, not just someone who reads from a script pointed at the screen. Sadly, this is way most (but not all) PowerPoint professors operate.