Ads can be useful for marketing moves, e.g. if you sell at discount or just a new product. Otherwise people would never know you have X too (or cheaper) because they remember that you didn’t last time.

But every time I turn adblock off accidentally or on purpose, it’s the same generic shit unrelated to my obvious interests. Nasal sprays, supplements, car dealerships, be-a-programmer courses. I have a non-zero, negative interest in these.