thumb's up for so what

A few years ago, I was giving a talk at UMBC, hosted by the Department of Electrical Engineering. Early on, I caught a student giving a "thumb's up" sign to his professor. Not bad feedback! 

But afterwards, I asked whether there was a reason for that feedback at that moment, and I received an interesting answer. Recently, the same group of students had received a talk on how to give talks, by a devotee of Edward Tufte. One of Tufte's rules of presentation is that the title of a slide should state not merely the "what" but rather the "so what?" 

So, this introductory slide got a thumb's up for its title, which, after all, could have been something boring like "Brain Images Sensitized to Different Contrasts."