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!”
The usual acne related ones, like washing my face more or using tooth paste on my spots. Turns out clearasil won’t fix your hormones.
Use olive oil instead of sun screen because it works better than SPF and isn’t full of chemicals.
When taking a taxi on a short stop over in Dubai, the taxi driver told me not to have blue hair (which I had) or no man will ever want me, while my then boyfriend was also sitting in the taxi, masquerading as my husband (we were wearing rings and just letting people assume we were married, which everyone did. Including the taxi driver!)
Work related: don’t make my code too “complicated” or my one coworker can’t understand it (read: my coworker doesn’t know what async means, and instead of him learning, I’m just not ever meant to do anything async… When processing huge amounts of data… Also, error handling is too hard, don’t do that either) yes, I will forever be salty about this. He deleted weeks worth of work while I had covid because he didn’t even try to understand it - his reasoning being “it doesn’t work anyway, so there’s no point in understanding or learning what I’m doing”