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!”
I got the same thing said to me but to go into math instead. I never listened to them. Now I’m looking for jobs and there’s a ton of openings for history jobs and I tend to feel a little smug about it.