Let me restate to see if you can get my point :-), since the point was that it's real darn easy to effectively end up with a page about strawberries that contains ad(s) for cream.
If Google won't show the ad you want on page X, then create your own "ad" for the given product/service category and put it on page X. Make your ad link to a page that is designed to attract the ads that Google wouldn't show on page X.
You get nearly the same effect as though you could make Google display the ad you wanted except a) the user who is interested has to perform an extra click and b) you quite likely get payed a better CPC due to the prequalification that extra click represents and the effect it has on SmartPricing, and c) you get an entire page (instead of little or no text on your strawberries page) to provide useful info that matches qualified visitors with the product(s) being advertiserd there and d) you get another chance to keep visitors on-site who were thinking about cream, but weren't really going to click on any ad for cream, and e) you get more detailed stats about how many customers are interested in cream, but not really enough to click on and ad, and f) you get 100% control over the "ad" that appears on page X (no Google T&C applies here!) without ever having to worry about MFAs or PSAs appearing there and, well, if you didn't get it by now, it ain't ever gonna happen :-).
Gets you to a much better place, IMHO, but everybody's entitled to their own :-).
Replacing (or augmenting, in certain cases) Google ads with house ads (that lead to Google ads) on strategically selected pages is one of the most untapped revenue resources in all of AdSensedom.