Depends upon your point of view. I'm mad at bad ads (deceptively written) that lead to bad sites. I've looked at my site and seen ads that make me say "Alright! Very much right on, exactly what I want to see on here" Then I go to the site (right-click, copy location, inspect url, go to it) and the site is one big pile of adsense ads with sometimes a copied article. Of no use to my visitors.
I don't think it matters how relevant or well crafted the ad is. The content of your own site, the nature of the traffic you get to your site and the relative daily stability of that traffic regulate what your visitors see. If AdSense system considers your site not worthy as a publisher - you won't get any hi-paying ads. The low-paying ads one will usually get in this case = MFA. It is that simple. Again. AdSense is a very sophisticated auction system. It is not just who pays the most - gets the traffic (advertiser side), it is also best publishers who get the best ads (publisher side). This is interesting. I don't have many sites displaying adsense - I only have one, so my perception is based on that one site. It is a 6-month old site with useful content on the subject and naturally occurring links from hi-PR pages and I don't think I ever saw an MFA link on my site. So, I still believe that your own site's quality matters.
This is google. Nothing is "that simple" Everything you said about your site I could echo for mine except the age. Subject area probably also comes into play. Available ad stock. A great number of things. You can spend a LOT of money on ads but have the actual payout per click be low and I'm sure google factors that in, as well.