Give me one example of retargeting “used effectively” that did not at least risk annoying its human target.
Retargeting only looks effective when viewed through the prism of tendentious math on the perpetrators’ side that ignores the collateral damage it does.
As for the little “x” in Ad Choices, you need the hands of a safecracker to click on it, and the opt-out feature of Ad Choices is hardly worth the effort, since it reaches only a small part of the whole adtech/adfraud complex, and offers no guarantees.
As for “After all, you must have encountered a product or service through some advertisements that proved useful for you as an individual or firm,” the answer is yes for plain old brand ads that I know were not stalking me, and never for adtech-placed ads.
I’m guessing that you are in the adtech business. (Correct me if I’m wrong about that.) Here’s the thing publishers, advertisers and the agencies between them need to realize: “ad-blocking software that completely encircles you” is exactly what hundreds of millions of people have chosen, on their own, in the open marketplace. That did not happen just because they hate advertising. It was earned by adtech practices, especially retargeting.