For example, showing you unlikely or imagined bike-related problems, to sell you useless protection gear or insurance after you get your bike. Showing you ads for motorcycles, because although you probably don't want one, someone who already likes bikes is more likely to buy a (more expensive) motorcycle, so that's where they'll direct their spam.
Targeted advertising is about manipulation, using knowledge of the customer to change their behavior. No one is going through those efforts to show you what you already want and save you a quick Google.
The ENTIRE POINT of an ad is manipulation. Advertisers wouldn't bother if people always ignored ads.
One the ads are more relevant.
Two because the ads are more relevant the advertiser makes far more money on them and therefore doesn't have to show you as many to fund their service.
But also, much of ads are scams, and the targetting helps the scammers find susceptible targets