I don't recommend swearing in a presentation as a general rule only because (unfortunately) you are sure to offend a least a small minority in the audience. But how careful does one have to be? A few years ago a received an email from someone who was in the large audience of a presentation I gave at a fancy hotel. The gentleman said he loved the contents of the talk and that he "had been a fan" but was very disappointed because of my "dirty language." That's right, I had uttered the phrase "pissed off" twice while quoting what an angry person had said in one of my stories that illustrated a point about the frustration of bad UI design. Again, I do not swear in formal talks or in front of young children, etc. (unless PO'd counts) but swearing is like a bold typeface: used well and used sparingly it is extremely effective and adds color and emphasis.

 Honestly, I do not know what the big deal is. Besides, swearing is healthy :-)
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