The aspect of things that are most important to us are hidden because of their familiarity and simplicity. - Ludwig Wittgenstein

Concerning that which cannot be talked about, we should not say anything.

That of which we cannot speak, we must pass over in silence

What makes a subject difficult to understand — if it is significant, important — is not that some special instruction about abstruse things is necessary to understand it. Rather it is the contrast between the understanding of the subject and what most people want to see. Because of this the very things that are most obvious can become the most difficult to understand. What has to be overcome is not difficulty of the intellect but of the will. [Nicht eine Schwierigkeit des Verstandes, sondern des Willens ist zu überwinden.]