The RMS anecdote is worth calling out:

Incidentally, this was the first time that I have ever been actively heckled during a talk. Despite conducting a rather loud personal conversation at the back of the hall during most of my talk, then giving me a massive thumbs-down gesture as I wrapped up, Richard Stallman decided he had heard enough and proceeded to take over the Q&A session for a bit of a dyspeptic rant about the 'iBad' and how Apple was subjugating children everywhere for their own evil ends.