5. The speaker ignores the audience's intelligence.
It astounds me how often this happens.
An audience can see through the fact that you are BSing them.
An audience can see through when you are spinning them.
An audience can see through it when you put lipstick on a pig.
An audience can see through your bait and switch.
An audience knows when you are paying false homage, when you fail to acknowledge failure, only focus on the positive, etc. etc. etc.
None of this is hard for an audience.
When you BS/spin/lipstick, you throw off micro-clues that betray you. The pace at which you talk, the thing you skip over, the way you lean, the part you dwell on, the texture of your voice.
You won't hear anyone starting to heckle you - almost all audiences are incredibly polite - nor will they even come up and tell you that they could see through your charade. They just won't respect you. And, they won't show up the next time.
I've given you tips of what to do for each reason the presentation sucks above. For reason #5, there is no out: Just don't suck. Respect your audience, respect their intelligence.
Bonus intelligence tip: We all speak to audiences of mixed backgrounds, professional experiences, job levels, and competencies. Presenting a story that'll cut across that mix is hard. Your strategy should not be to "dumb your story down." Your strategy should be to simplify complexity. You retain the intelligence; you make it accessible for an audience of mixed backgrounds/skills.
Bottom-line: The first time I got on a public stage on Jun 01, 2005, I was scared out of my wits. I was on stage today (Cathy took the pic), and I was scared out of my wits before I went on. During that time period, I've made lots of mistakes, I've sucked - including the reasons above. But, I've also watched some of the world's most extraordinary speakers who've helped me create a set of exceptional standards that I work every hard to meet. In a very small way, I hope my accumulated lessons do the same for you.
Never compromise. Your content. Your values. You.
Break a leg.
-Avinash.
PS: This edition of TMAI started as a tweet, with four of the above five reasons. The thread that followed that tweet has great conversation in it, with lots of wisdom from the crowd. Do check it out.