So, whenever you see "Quality Score", I want you to read BIG Score: Best Interests of Google. This will remind you that QS has nothing to do with quality and is designed to maximize revenue for the borg. For example, the dominant factor of QS is <i>not</i> relevance, but is, in fact, click-through rate. (Google defines that which results in you paying more money to them as "relevant.") Next up is account history, for much the same reason that e.g. an airline will throw you off the plane if Mr. Super-Diamond-Elite really wants your seat.<p>Defaults are also set to be notoriously BIG. For example, no responsible AdWords professional would suggest putting search and content ads in the same campaign, because the performance of the two is not comparable and this will result in massive overspending on the Content Network. Guess what the default behavior is? Yep, both checked. Default ad rotation strategy? BIG (n.b. which is sometimes in the best interest of the advertiser, too, if they're doing it wrong). The behavior of various match types? BIG etc, etc