''...when dictating the Mahabharata to Ganesha, the poet in order not to be outstripped by his divine scribe—for it was Ganesha's stipulation that not for one moment should he be left without matter to write—threw in frequently knotty and close-knit passages which forced the lightning-swift hand to pause & labour slowly over its work. To a strenuous mind these passages, from the exercise they give to the intellect, are an added charm just as a mountain-climber takes an especial delight in steep ascents which let him feel his ability. Of one thing, however, we may be confident in reading Vyasa, that the expression will always be just to the thought; he never palters with or labours to dress up the reality within him.'' 

Sri Aurobindo- Notes on the Mahabharata

17th century Rajasthani manuscript of the Mahabharata depicting Vyasa narrating the Mahabharata to Ganesha, who serves as the scribe. [wikipedia]