1. “Thank you for your concern.”
Example prompt: “I wouldn’t wear that if I were you.”
What can they say in response—”I wasn’t concerned, I was just trolling”? Exactly.
2. “Because I want to.”
3. Upbeat: “Yep, it certainly is unfortunate.”
Example prompts: “Your kitchen is such a mess. How can you live like that?” “Your shoes clash with your outfit.” “What a terrible day for your [special event]—such bad weather.”
They’re picking something that may be a sore spot for you and trying to make you feel bad about it. But just because it’s messy/ugly/whatever, doesn’t mean you need to feel bad (or care)!
Repeat after me: “I am at peace with myself and my limitations.”
4. “I sure wish I could, but I can’t.”
Related: “I could, but I’m not going to 😛 ”
5. -shrugs- “Maybe I am.”
This works in response to accusations like “You’re being selfish!” Obviously, it is not selfish to do what you need to do to protect your own sanity, but if they want to call that selfishness—so be it.
6. “That’s between me and [whoever].”
(Unspoken: “And therefore it’s none of your business.”)
7. “I’m not willing to discuss that.”
If they push it:
- “I’ve said what I have to say about that.”
- “Isn’t there anything more interesting we could talk about?”
- “I’ve said that’s not up for discussion. You can either drop it and let us talk about something else in peace, or I will leave—now.”
8. “Please never contact me again under any circumstances. Goodbye.”
(Say this once in writing, then block them everywhere and do not respond to any other attempts to contact you.)
9. “What are you looking at? Can I help you?”
If they respond with something lewd: “Why would you say that? Ew, gross.”
Further escalation: Point at them and get the attention of bystanders— “Excuse me, this guy is following me/this guy is being really creepy.” Get out your phone and start filming them.
Further escalation: Stop in your tracks, square up and stand your ground, look them dead in the eyes, and say loudly, “GO. AWAY. I don’t want to talk to you. Leave. Me. Alone.” Repeat until they wander off.
Further escalation: Scream at the top of your lungs, yell for someone to call 911, and run; or fight, kick, scratch, and claw out their eyes.
10. “Hmm, what do you mean by that?”
Example prompt: “I’m surprised you chose such an interesting outfit.”
Crazy people often phrase things passive-aggressively; you might get the sense they’re insulting you, but it’s not clear.
Call them out like this, by saying “Hmm, why do you say that?” in a completely neutral tone of voice, and they will change tack and pretend they meant to say something neutral/friendly all along.
Go with the direction change. You already know you can’t trust this person; you’re just trying to have as pleasant an interaction as possible, in the meantime.
11. “Well, that’s nice that that’s your opinion.”
You must phrase this in a way that comes naturally to you, so you can say it in a pleasant, upbeat, offhand tone of voice. You’re basically saying “Opinions are like assholes. Everyone has one,” but in a more positive/neutral-sounding way.
(If they’re like the person I said this to, they will sputter “That doesn’t even make sense,” and leave you alone. Success.)
 I did not come up with this magical phrase—I read about it many years ago on Jezebel or The Hairpin or something (upon Googling what to say in a tricky situation)—but now I can’t find the article anywhere 🙁
Update (April 5, 2021): To clarify, I don’t endorse leaving a loving partner because you’re bored (which is how some people told me the poem comes across).
I needed to hear this message—that it would theoretically be okay to leave “even if your leaving would devastate him,” “even if you once said you would stay”—in order to leave an emotionally abusive relationship. (Since I felt that I didn’t have any “good reason” for leaving, just the feeling that something was not right—when the truth was that he put on a good show for other people and I was too ashamed to admit what was really happening.)
 As advised in the book Stop Walking on Eggshells: Taking Your Life Back When Someone You Care About Has Borderline Personality Disorder by Paul Mason and Randi Kreger.
P.S. Another recommended read (and inspiration for the title of this post) is the book Talking to Crazy: How to Deal with the Irrational and Impossible People in Your Life by Mark Goulston.