Here's my experience... just because you're speaking to a crowd of people or an individual that you have one thing in common, don't assume that you can be as casual as you wish.
At this point, all I can say is that I'm grateful that I learned something. It had a most significant impact on me and it is unlikely that it would happen again. It may be your intent to convey your thoughts through very relaxed rhetoric, but there is absolutely no guarantee that the recipient interpret your message exactly how you intended it to be. Therefore, the impact on the recipient can often be less than desirable. Put yourself in the shoes of the recipient and see if your message is diplomatic.