I might be grouchy, but I don't want any ads to be useful. A useful ad is just a successful ad. The endgame of the most successful persuasive ad is mind control. If some ad genuinely convinces me to buy a thing, while I may really be glad I bought that thing, I still have this feeling of being used and would prefer it didn't happen.

(when I've seen a useful ad for something I really want, I've often been able to find nearly the same thing from someone else for less. They can afford to charge less since they're not paying for ads)