Of course you do. But don't mistake me, it has nothing to do with them smiling. It has everything to do with them experiencing this feeling: I like you, I respect you. When an audience warms to you like that, your believability and your ability to persuade take a significant jump in the right direction.
How to make that happen? Well it's hardly a surprise - if you want them to feel that way about you, you have to feel that way about them.They can't help but respond, even when they consciously disagree with your topic.
But of course self-consciousness gets in the way. It masks your natural liking and respect for others. Too many naturally warm people make presentations as if they came directly from the undertaker. The audience might feel sorry for you, but they can't warm to you. So the real challenge is how to allow your normal liking and respect for others show through in spite of self-consciousness.
Here's a solution that works well for many trainees.
Practise showing warmth.
Seriously. Get in front of the bathroom mirror and imagine bumping into a friend you haven't seen for a while. A friend you like and respect. Look at the subtle changes happening in your face muscles - especially around your eyes. Don't allow a big smile. Stay with the subtle changes. Now here's the important part. Next time you meet a real person you like and respect, be aware of those physical changes.
In front of a real audience, make those physical changes happen until it becomes natural.
And do yourself and your audience a very big favour. Make it happen right from the first moment - when you're walking up to the front, when you're in position, and when you're looking around at everyone and greeting them.
By the time you've said, 'Morning everyone', the audience should already be warming to you.
Even when they disagree with your opinion or decision.