So what have you done here? You haven't done a trick. You haven't told someone their fortune. You've just told them something about themselves that might be useful to remember in a particularly trying time.
I've performed this twice in my life for two different people and both got somewhat emotional and said almost identical remarks. Something along the lines of, "That is exactly what I needed to hear right now."
B-b-b-b-but Andy, you've always said you don't like when magicians or mentalists play things as real. Aren't you playing this as real? Isn't this being manipulative?
Here's what I don't like. I don't like when people try to make others believe they have a power they don't really have. What I mean is, I don't like magicians who want others to walk away from their performance believing something untrue. I think that's bad for the spectator, bad for magicians, and bad for the art of magic.
This, however, is not a magic trick. It is a way of you sneakily introducing just what someone might need to be reminded of at a vulnerable time in their life. And shining a spotlight on that message in a way which might allow it to be accepted more than it would if you were just to offer it as some advice.
This isn't like trying to justify being a fake psychic by saying, "Well, I make people feel better." That's just a bullshit rationalization. You're not taking money for this. You're not invoking some phony power. And you're not lying.
I can comfortably say you're not lying because what's written on that card is true of essentially everyone. Are you in the midst of some upheaval in your life that feels overwhelming? I promise you that you are underestimating your ability to deal with that change and that you have vast reserves of strength that will get you through this time.
We may need to be reminded of it from time to time, but that's just a statement that's true of the human animal. It's essentially a self-fulfilling belief. You might say, "Oh no, not me, I'm bad with change." But look, if 99.99% of the population, including everyone you know and love, died in a zombie outbreak, within two days you would be doing a fucking shoulder roll out from behind a parked car to blast some zombie's head off. You have the capacity to adapt to change, you just don't like to because it's a pain in the ass. I get that.
You can put some other positive message on the backs, of course. Just try to make it something that A) is true, and B) protects or enhances the other person's self esteem. (That should generally be your goal with any interaction with someone you care about.)
Tear Them Down
Of course, this can be used for the opposite purpose as well. In fact, I'm sure this idea will be much more popular than the previous one.
You're performing magic, maybe at a party with friends, or even in a professional walk-around situation. Some guy is being a total cocksucker and annoying you and everyone else. You've put up with him for a while but now you've had enough.
"You're a lot of fun," you say to the a-hole. "Can I try something with you real quick? I've been studying some psychological research that says people's choice of playing card says a lot about them. This isn't like fortune telling or something. Essentially they reverse engineered it by interviewing 1000s of people, asking them to name any card in the deck, and then they seeing what the people who named those cards tended to have in common."
You pull out a deck with phrases on the back of each card.
"I've actually been conducting the test myself in an unofficial way and it's astounding how accurate this is. I don't want to influence you by showing you the front of these cards just yet, but for example, people who named this card tended to be entrepreneurs, people who named this card tend to excel with languages, people who named this card were generally children of divorce." The cards indicate these qualities with definitive statements and the percentage likelihood of this being true based on the study.
For example, those three cards would read:
96% - You are an entrepreneur
99% - You are good with languages
98% - You are a child of divorce
You continue to spread and show all the different traits that the cards might indicate. Most are positive or neutral.
"So, just for fun, name the first card that comes to your mind? The Queen of Clubs? Okay, let's see... Oh this is interesting, and pretty specific." You turn it over and it reads:
100% - Your dog's butthole smells like your cock
"It's consensual, though, right? I mean, I'm not sure if it's defensible either way. But I truly hope you're not forcing yourself on him. Or are you just rubbing up against it without actual penetration? I guess that's better..."
Okay, so it doesn't need to be that crude (although that's probably how I would do it). It could say something like, "100% - The last time someone referred to you when you weren't in the room it was as, 'That idiot.'" Or, "100% - You are the most dispensable one in your circle of friends. Deep down, you know this." Or simply, "100% - You are not exceptional in any way."
Again, this is not really a trick. Is it a heckler stopper? Kind of. I mean, if you consider making someone cry or instigating a fistfight to be stopping them from heckling, then it definitely is.