When an object is significant and important what makes it hard to understand is not the lack of some special instruction in abstruse matters necessary for its understanding, but the conflict between the right understanding of the object and what most people want to see. This can make the most obvious things the very hardest to understand. What has to be overcome is not a difficulty of understanding but of the will.

MS 213, as quoted in Kenny, The Wittgenstein reader, 2nd edition, Blackwell, 2006, p. 46