A must-watch for everyone. This has to be one of the most amazing talks I've seen, super-impressive and useful. Life-changing. It's about how to improve all your relationships, interactions, your life, the lives of everyone around you, the world etc. How to communicate far better, leave people glad they met you etc. While being totally honest at all times–I presumed it'd be about body language, or manipulation, or..using people, or something.
So I watched another of his talks, How to Build Trust with Anyone, it was just as good.
https://www.youtube.com/watch?v=dqzH5GJwrnk