I had a lot of such moments, including:

• Most recent, I had the option of either buying an app from the app store to train myself on the piano, or vibe coding a web app to connect with an attached MIDI keyboard and accept an uploaded MIDI file and give me an experience like Guitar Hero, and Claude did this in two prompts of their free (not paid subscription) tier, where the second prompt was just the word "continue".

• First demo of InstructGPT (predecessor to ChatGPT), because I remember how much worse the state of the art in NLP had been, and because I hadn't expected instruction following from the quality of continuation seen in GPT-3.x

• 2019, "This Person Does Not Exist"

• 2016, seeing style transfer and similar working (https://github.com/awentzonline/image-analogies) and what would now be called Deep Fakes (back when Two Minute Papers videos were <2 minutes long: https://www.youtube.com/watch?v=_S1lyQbbJM4)

• 2015, when I (in retrospect, foolishly) believed Tesla about their over-the-air software update that introduced self-driving: https://www.popsci.com/tesla-cars-become-autonomous-overnigh...

• 2013, word2vec, "man" - "woman" ~= "king" - "queen", again because of knowing how bad the state of the art in NLP has been

(If you're wondering why "uh oh" from that, consider value in automating propaganda, and surveillance opportunities for automating comprehension of slang/cants like Polari).

• 2010, seeing the demo video of Word Lens: https://www.youtube.com/watch?v=h2OfQdYrHRs