Real life goes on and on, whereas fiction is packaged into neat parcels: a novel or a short story.
Real life contains all the boring bits, the brushing of teeth, the walk to work, the ten minutes faffing around before making that call. Fiction cuts out all the boring bits (or should do!).
Real life takes time - a life time, literally. Fiction is the edited highlights compressed into a few minutes or hours of reading time.
Real life is full of coincidence, missed opportunities, inconsequential happenings. Fiction avoids coincidence, grabs every opportunity, and all happenings have consequences.
Real life may well see the good go unrewarded and the undeserving flourish. We may like to dream that Simon Cowell is unhappy deep deep down to balance his incredible success over the last decade, but to me he looks like a man who's pretty content with life. Happily, in fiction, the good can win and the baddies get their come-uppance.
Real life hampers the writer's choices as they worry about offending family and friends or getting it wrong. Fiction gives the writer free rein to do whatever they want or imagine.
Fiction gives the illusion of real life, but it is just an illusion. Writers make it up, and sometimes they make it feel more true than real life. Fiction isn't real life - it's better.