Hey kids, here’s a neat trick: at any point during a conversation with someone, remark, “Hey, you don’t need to act all defensive.”
The other person now has two options.
A) They can agree that, yes, they are acting defensive.
or B) They can remark, “I’m not acting defensive.” In saying this, of course, they are now in fact acting defensive.
So despite whatever was actually going on in the conversation, they are now, against their own will mind you, acting defensive. Congratulations, kids: you have just controlled another human being’s mind. Use your powers for good.