This happened a few days ago and I'm still a little annoyed about it.
I was eating lunch alone at a small restaurant, just minding my own business. The woman sitting at the table next to me, complete stranger, started making comments about my food. First it was a "oh that's a lot" with a little laugh. I smiled and ignored it. Then it was "do you always eat like this" and I just kind of shrugged.
But then she leaned over and said something like "you should try eating lighter, it's better for you" completely unprompted. I didn't ask. I don't know her. She has no idea about me or my life.
I looked at her and said "I didn't ask for your opinion, please mind your own business." Not loudly, not aggressively, just firm. She looked genuinely offended and made a comment under her breath about people having no manners these days.
The friend she was with gave me a look too like I was the rude one. I don't think I was wrong but the way they both reacted made me second guess myself for a second.
AITA