I've chosen to use circles as a graphic element because they relate beautifully to the geometric form of Century Gothic.
That could be a justification for a design choice, and it would make sense, I think. I e you are being consistent, basing your design choices on already existing elements.
That's all fine and dandy, right? However, equally often you hear the opposite as a justification:
Here, I've used squares as a graphical element to break the monotony of the rounded Century Gothic.
And that's like yeah, cool, see what you did there.
How come it seems two complete opposites seem to be such great justifications, really?