This is a rather odd AH, but I am a huge fan of Christopher Reeve and going through his bio/history I was surprised to see the number of important movies he turned down: The Mutiny, Officer and a Gentleman, American Gigolo, Arthur, World According to Garp, Urban Cowboy, Romancing the Stone. I began thinking about what the repercussions would have been had he selected certain movies. The role Reeve turned down in The Mutiny went to a young, unknown Mel Gibson and served to really launch Mel's career. Take away that opportunity, Gibson may not have made it. Lethal Weapon may have been miscast (Gibson made that movie) and the franchise could have been stillborn, no Braveheart, no Passion of the Christ. If Reeve had taken Officer and a Gentleman and American Gigolo, Richard Gere would have lost out on his chance at Hollywood stardom. Had Reeve taken Romancing the Stone, Michael Douglas' career would not have rebounded and the classic Gordon Gecko character may have failed under some other actor and other famous fare including Fatal Attraction, Falling Down, and Basic Instinct may have foundered.
Then there is the issue regarding Morgan Freeman. Had Chris been in acting solely for the fame and money, he never would have pushed to make Street Smart, a small budget movie he was obsessed with seeing filmed. No Street Smart, no opportunity for Morgan Freeman to play a pimp and win an Oscar for Best Supporting Actor establishing the man for later years. One good trade off is there would be no Superman IV (that flick only being made so Reeve could make Street Smart).
I can't fault Chris for going for what he viewed as the more artistic movies (Somewhere in Time, Death Trap, etc.). It was only later in his career that Chris began to realize what his choices meant for his career when he began to be passed over for roles (Bonfire of the Vanities, Pretty Woman). The guy had amazing talent. If he had been smarter in his movie choices who knows how far Chris could have gone.