The flock: It remains clear to us that the flock remains very important. Being close (but not too close) is the budgie goal regarding other budgies. However, it is clear that Sutcliffe really just wants to be near Mary ann. Therefore, the flock is not homogenous in it's appeal.
The highest perch: The budgies seem to use most of the perches in the cage, and the lowest perch does not equate with low on the social totem pole per se. Budgies do have a fear of what is overhead and strongly dislike having activities (such as human hands) over their heads, but, sometimes seem to like to hang out on the lower rungs. The perch preference does not seem s simple as once thought (on this blog).
Millet seed: it is true that treats, including millet seed, are highly motivating. As a metaphor for treats, millet seed remains. But I think that other treats, especially, very fresh grasses with new seeds, certain types of greens, and strawberries rank highly. And, budgies have preferences. Some prefer greens, others, strawberries.
Not mentioned as a true passion of budgies in this list of three is showers. Other posts have commented on budgie bathing, and perhaps it deserves to be listed along with these other budgie favorite things.