There's a beautiful balancing trick which makes any talk, lecture, or public speaking performance work well.
It's something I think hard about when planning an event, and then analyse afterwards, to see if it was about right.
This week, I was lecturing in Social Media to some of the excellent entrepreneurs at Cambridge Judge Business School.
Given the importance of images online, part of the lecture was about how to take pictures.
I could have just waffled on about the rule of thirds, the use of foregrounds, backgrounds, and angles, but it's a principle of mine that you learn best by doing.
So... I generated an appropriate backdrop, and, as a jolly fun exercise, got the group to take photos of themselves in front of it.
I hadn't tried this before, and wasn't sure how it would work, but I think the pictures tell their own story.
I'm pleased to report there was a great buzz after the lecture, and the feedback was good.
The entrepreneurs also did their homework, and used the photos for social media posts about their day.
But there's an important point amidst all this fun.
Any fool can act the ass, and make a talk out of lots of gags, gimmicks, and silly exercises.
But how does the audience come away feeling after that?
I've been there, and remember the distinctly unsatisfying sensation.
It was a kind of sickliness, a feeling that some would be ok, but too much leaves you unfulfilled and queasy.
Just like a meal that's all pudding and no main course. No substance, in other words.
The trick of any talk, in my humble view, is all about finding just the right mix of fun and entertainment, but information, too.
My game with the selfies wouldn't have worked unless it had real learning to it.
It's just the same when I give a talk about my books, and TV work.
I could pack the whole thing with daft stories, like the time we chased down and filmed the wrong dogcatcher, or when I had to thaw out a frozen otter in a restaurant's toilets, or the way we scaled the walls and broke into a police training college to get a story.
Instead, I also talk about some of the sobering moments, the like of which a BBC TV reporter comes to know all too well.
Covering terrorism. People losing their jobs and homes. Natural disasters.
Because if there's one thing you can guarantee everyone in each and every audience has a stake in, it's this amazing phenomenon called life.
Which means we've all known the highs and lows in our times.
If any talk, lecture, workshop or whatever is going to hit home, it's got to reflect us, our experiences and our understandings.
Which is where the beautiful balance of the light and shade of life comes in.