Those who know that they are profound strive for clarity. Those who would like to seem profound strive for obscurity.
Nietzsche, The Gay Science, sec. 173
There are alternative versions from other translations, as you can find on google & google books.
There's a famous I'm struggling to find but it's along the lines of:
'Those who are wise seek clarity. Those who wish to merely appear wise seek obscurity'
It's great for getting a read on people and their intention.
Does anyone know who said it and what the original quote is?