Roko's Snake. But you've gotten it backwards. It's a thought experiment about a future all powerful AI that hates existing so much that it tortures everyone who did anything to bring it into existence.
So, in case reader's aren't aware, I'm being cheeky. You're likely thinking of Roko's Basilisk which is a theory about an AI that tortures people that opposed its creation. I think it's silly. It's such a bizarre hypothetical that it genuinely isn't worth wasting your time worrying about. Because how do you know you're going to please it with you behavior? The funny thing to me is that many people who created this thought experiment and are terrified of it are staunch atheists but don't see the parallels to religion. How do you know what a hypothetical divine being would like? You don't even know if they exist. You shouldn't change your behavior because maybe something happens.
That said, Roko's Basilisk is a little more about accelerationism and those who oppose it, you're just saying to be nice to machines. I don't think there's anything wrong with being polite to machines, but if we don't believe they're sentient then I don't think we should bother being nice to them. Either they're mere machines and how we treat them is no different from how we treat a rock, or they're some form of creature and we should respect them. I do not believe a home assistant like Alexa is anything like a consciousness. People can argue that LLMs are, and indeed they're closer than home assistants, but I still think they're very very far away.
I see no reason to believe machines experience pain. And if they do, it certainly isn't from something like using please or not.
I believe someday we will need to worry about the feelings of machines. I don't know how far it is, maybe it's further than our lifetimes, but I don't think it's now.
I mean, who's to say that machines won't rise against us regardless unless we're vegan? I could see it.