From last week:
I'm at a large math conference; the travel disrupted my internet access this week. Many of the talks are good in that they are understandable to a majority of the audience: audience members learn something mathematical from the talk. Some of the talks are not so understandable. Sometimes in mathematics we give people a free pass on understandability because we think they are brilliant. (This is actually coming up strongly as I attempt to work through an elementary example in a paper I'm reading: authors, I know you're brilliant, but could you define your notation and not leave all the hard work to the reader? If I could do that work I would have written your paper. Seriously.)
So, in your heart of hearts, would you rather listen to a talk at a conference that is understandable or one that is not understandable but might make many people think, "He must be really smart... 'cause I don't understand what he's saying!"
Set out assumptions first: assume you are not a graduate student. Assume you are the target audience for the conference and talk, and are reasonably knowledgeable about the area without being a world-class expert. Do you want the understandable talk or the seemingly brilliant talk?
We all know what the answer should be to the first one; I'm mainly asking in order to check my assumptions. Second question: which speaker do you secretly or unconsciously respect more after the talks?
I have heard some folks confess that secretly if they feel dumb after a talk, they respect the speaker more.... and if they understand, they conclude that the speaker's work wasn't that hard.