Ian Leslie investigates why our brains respond well to difficulty. One example:
You might have thought any tool which enables a writer to get words on to the page would be an advantage. But there may be a cost to such facility. In an interview with the Paris Review Hughes speculated that when a person puts pen to paper, "you meet the terrible resistance of what happened your first year at it, when you couldn’t write at all". As the brain attempts to force the unsteady hand to do its bidding, the tension between the two results in a more compressed, psychologically denser expression. Remove that resistance and you are more likely to produce a 70-page ramble. There is even some support for Hughes’s hypothesis from modern neuroscience: a study carried out by Professor Virginia Berninger at the University of Washington found that handwriting activated more of the brain than keyboard writing, including areas responsible for thinking and memory.