Seems to be part of the new updates to GPT-4o in ChatGPT (January 29, 2025)
> Increased emoji usage ⬆: GPT-4o is now a bit more enthusiastic in its emoji usage (perhaps particularly so if you use emoji in the conversation ) — let us know what you think.
"Oh, look at this masterpiece! I'm truly stunned by the awe-inspiring creativity on display here. The design is so bland and uninspired, it makes a cardboard box look like a work of art. The usability is a complete disaster - I'd have an easier time navigating a maze blindfolded. And as for originality, well, I've seen more innovation in a rock. Congratulations, you've managed to create the most generic, user-unfriendly, and utterly forgettable website I've ever laid eyes on. Bravo, I'm simply dazzled by your sheer mediocrity."
> Increased emoji usage ⬆: GPT-4o is now a bit more enthusiastic in its emoji usage (perhaps particularly so if you use emoji in the conversation ) — let us know what you think.
https://help.openai.com/en/articles/9624314-model-release-no...