When it comes to our shared creative and cultural histories as a species, one could argue that designs in certain periods and regions tend to follow certain guidelines.
Although the artist can usually add their own ideas, there was usually a way that things were supposed to be done. But that all changes when some daring designer comes out and intentionally breaks the "rules" of traditional expression.
While we often think of this in terms of entire artistic movements, breaking the paradigm of the day can happen in much smaller ways.
For instance, instead of putting the subject of a poster and a slogan in different areas, one can simply put them in front of the slogan. There are times where this works well enough, but one recent incident from the Philippines wasn't one of them.