14. Robert Zemeckis owes one to Terry Gilliam and Barry Sonnenfeld.
The Movie Blog
Barry Sonnenfeld, best known for his cinematography career and directing Get Shorty, and Terry Gilliam, director of Monty Python and Fear & Loathing in Las Vegas, both turned down the Forrest Gump directing gig. Robert Zemeckis read the script, knew the movie was going to be special, and immediately signed on.