I do the same as many of you when I go grocery shopping; I look in my cart and wonder what someone else would make of its contents. I used to buy a lot of frozen meals (like those Healthy Steamers, or Stouffer's or whatever) to bring to work with me for lunch. And because I only would go for groceries once a month, I would really stock up. I'd imagine people would think I had no idea where my kitchen was or how to use anything in it, LOL.
More on-topic, I was once fostering a litter of baby puppies for a local rescue; they'd been found in a local dump, along with their mother, who died a day or two later. The pups were still very young, like their eyes weren't even open yet, and because it was quite late in the evening and no pet stores were open, I ran to the nearby drug store and picked up some powdered, lactose-free baby formula. (Not the best thing for baby pups, but it works in a pinch until you can get your hands on actual puppy milk formula.) These two older ladies were behind me and I could hear them commenting on "babies having babies" and how shameful it was that I was a "teen mother" and so on. (For the record, I was 24 at the time. Hardly a baby and perfectly old enough to be married and having kids, if I'd wanted.) I turned around, raised my eyebrow and said, "That's quite the assumption you're making." then I just faced forward again, got to the cashier, paid for my stuff and walked out. I wasn't buying the formula for my baby, or even a HUMAN baby, and yet it seemed surprisingly easy for those two women to judge me and automatically assume I was an unwed teenage mother. "Trashy" was about the kindest thing they had to say about me.
However, I did choose to take it as a compliment that at 24, I still could be mistaken for 16