Pinterest SHOVES a lot ff their "promoted" and "picked for you" pins in your feed. By doing this, its really the visual equivalent of making you look at everything in your junk mail folder.
It wasn't always like this. YOU could decide what you wanted to see. I get that Pinterest needed to be able to monetize their site. However, the way they are going about it is just a turn off. I would have rather paid an annual fee. Now, I just go to the site a lot less.