Victor Semo preaches something called Grapho-Persuasion, which is something to do with knowing the personality of someone (handwriting analysis helps) in order to help persuade them. To that end he has published a book, gives seminars, and has produced a deck of cards called “persuasion note cards“.

Along with the cards come several games (training exercises) to familiarize yourself with the principles and evaluate their importance.

I would say that when it comes to knowing someone’s personality, playing games with them helps.