Seeing Kafka on this page made me remember the other one of his quotes, relates to thread here:
I think we ought to read only the kind of books that wound or stab us. If the book we're reading doesn't wake us up with a blow to the head, what are we reading for? So that it will make us happy, as you write? Good Lord, we would be happy precisely if we had no books, and the kind of books that make us happy are the kind we could write ourselves if we had to. But we need books that affect us like a disaster, that grieve us deeply, like the death of someone we loved more than ourselves, like being banished into forests far from everyone, like a suicide. A book must be the axe for the frozen sea within us. That is my belief.
I agree in thinking it's what art should do, 'shake one up', and change beyond point of no return. And it's what I seem to often describe as 'happiness' when finding a piece of art that does this.
My most frequent (minor) disagreement with my mother is in relation to theatre (that she often attends), but in order to 'ease the stress of everyday life' and 'laugh' and 'forget her worries'. Not saying she's fully in wrong here but we do seem to have a slightly different definition of happiness it seems.