You are responsible for your own emotions. Recognizing that doesn't make you a zen robot. You can still feel. But don't put those feelings on other people and make them responsible for making you feel the way you want to feel.

You can recognize patterns for your emotions, like "I get sad when people make fun of me", but that doesn't mean that you have to be sad when people make fun of you. Recognizing the distinction is what gives power to change.

And sure, there are limits. The feelings that arise when tortured for example are rooted in physiology and near unavoidable. But I suspect that John didn't let you down by waterboarding you.