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!”
My dad once told me that if my relationship with god was good, my grades would take care of themselves. I know what he meant was, “if you do the things god wants you to do, you’ll also be doing well in school”, but it’s still horrible advice.
More recently, my mother-in-law has been saying to my wife that she wishes that my wife could have faith in god’s plan because it just helps her in own life so much. I always roll my eyes at this. If there is a god, and he has a plan, his plan sucks ass and he plays favorites for sure.