"What if I'm wrong?"
--> A question I like, especially on very touchy and personal issues.
Your first thought will probably be to say, "Well, it'd be a good thing to do anyways!" ... because that's just what people tend to do when considering being wrong.
But dig a little deeper. What if you were really wrong? Like, not just the wrong course of action, but what if your whole idea of the setup and cause and effect and payoffs and long term consequences of your actions were flawed? What if you made a serious mistake somewhere in your evaluations, and you were going to get the opposite result of what you wanted? What if you got a horrific result?
History is obvious in retrospect, but sometimes it's also obvious going forwards. If Pol Pot had stopped and asked, "Hey, what if I'm wrong and it's actually a bad idea to kill everyone who speaks a foreign language, runs a business, is educated, or has a background as an urban professional? What if I'd be permanently destroying Khmer society instead of delivering it?"
More importantly - what if French intellectuals had asked the same question in Paris. "Hmm, perhaps this Monsier Pol Pot is not such a good guy? What if we are wrong in this one?"
So, ask what if you're wrong. And seriously consider it. What if you're really wrong in your political positions? In your religious devotions? In your daily habits? In how you treat (or don't treat) people? What if you've got it backwards?
What if cracking down on crime caused a lot more crime? What if treating criminals compassionately made them more likely to go completely insane, have worse lives themselves, and ruin others' lives in the process?
What if your safe job is actually a trap?
What if your favorite food is making you fat and diabetic and killing you?
What if you're slowly killing the person you're trying to save? What if they're slowly killing you?
What if getting your preferred politics turned your society and culture into an apocalyptic wasteland?
What if your favorite leisure activity is wrecking your mind, making you stupid, and holding you back from heights you can't even imagine from where you're at?
What if being "ultra-hardcore" at the gym is likely to cause injury and destroy your strength, flexibility, and health? What if resting more actually produced larger, safer gains?
What if working less meant more production? What if working more meant better quality of relaxation and more quality of life? What if pursuing less status made people like you more? What if not shunning status let you actually accomplish meaningful and important things?
What if you're wrong?
Don't ask it too often. Second guessing too much will make you go crazy. But occasionally, really honestly...
What if you're wrong?