I did once have someone in my audience slide off his chair after falling asleep. But it was only once and it was a program for the elderly right after dinner time. When someone else's hearing aid went off, he woke politely. Except for that one time, I have mostly kept my audience in their seats and quite attentive. I am not too modest to say that more than once, people have gotten up after my talk and offered heartfelt applause. In balance, I am an effective lecturer.
Having offered talks to many audiences, professionals and lay, I would say that the attraction they have to my presentations lay in good measure to the issues I address; most often ones that are not addressed by other professional but deeply felt by the lay person and the general artist and art teacher. The issues are: