It holds for all fiction, of course. 'Real life' is always weirder and richer than fiction. There's more of it; it's raw and unfiltered. But science-fiction and fantasy writers are especially susceptible to the neurotic impulse to validate their imagined worlds by cramming in details and explanations and descriptions of the quotidian elements of life in their elsewheres - tours of the automatic creche, the air factory, the steam-driven information net, plumbing. There's a point quickly reached, with detail, that numbs the reader's sympathetic imagination and flattens the affect of the narrative. It's why all utopian fiction is basically unreadable.