For the longest time I was getting Amazon ads on Instagram that were for products I had recently viewed - even viewed less than an hour before in some cases. Moreover, the Amazon account we use is my wife's, which we pay for Prime on. I would look at something on my phone, which is logged into her account, and then see the ad show up in my Instagram feed that day or a few days later.
Now, I get 90% ads for car parts and car accessories. I don't have a car, I don't drive, I don't have a license, and I don't even like to be in a car, but for whatever reason Amazon (or Instagram?) ads are assuming that what I really want are car parts and car accessories that I don't recognize, can't use, or don't understand.
It feels very stupid to me that those are the "default" ads I'm getting, even though I never tap on them for obvious reasons, but it's reassuring to know that they went from knowing exactly who I am and specifically what I had been looking at to having no clue whatsoever anything about me, or who I am or what I like.