Good writers on making effective presentations say that a top priority is knowing your audience. Let me add "and think hard about why they are at the event." Usually when I speak, people have come to hear about the topic I'm speaking on.
Yesterday I spoke to a kind of gathering I'm very familiar with: ministers and elders from churches in my denomination. What I didn't factor in was that they were there primarily for a business meeting -- my talk was well-received, but nobody had come specifically to hear it.
I think that accounts for a difference in tone, a kind of hurdle that had to be gotten over to get my message across.