I’ll go first: “You have to have children when you’re young,” told to me when I was in my late 20s, with no desire to ever have kids, and no means to support them, by someone divorced multiple times with at least one adult child who does not speak to them.
Also: Responding to “How do I deal with this problem?” questions with “Oh, don’t worry about it, it’s enough that you’re even thinking about it!”
And not me directly, but some years ago when my friend and I were both desperately seeking work, and running up against the “you need experience to get a job to gain experience” conundrum. His mentor told him to stop being so precious, and get a boring corporate job with a pension, maybe one that would pay his law school tuition. It wasn’t a thing yet, but wow, it would have been the perfect time to reply, “OK, Boomer.”
That’s like when they tell you to “pound the pavement” and ask to speak to the manager when you bring back your hard copy job application in person. It’s hard to even continue a conversation with someone who’s that out of touch.