Any kind of anthemic song for the most part they're on the positive side of things. It's not hard to identify when a melody is just one degree too complicated or one degree too simple and where that line of pop memorability lies.
And of course pop music is all about memorability and simplicity and positive messages and a little dash of joy.
In the 1970s we got nouvelle cuisine in which a lot of the old rules were kicked over. And then we had cuisine minceur which people mixed up with nouvelle cuisine but was actually fancy diet cooking.