Robbie Richie
There is always drama in Hollywood, even on the wholesome set of happy days. Robbie Benson was originally set up to play the character of Richie, but he wasn’t exactly excited about the part. Garry Marshall felt that someone else would probably be better suited to the role anyway, so the two got to talking. Together, they conspired for Benson to throw his audition and therefore lose the position to someone who would want it...
Vietnam Veto
The part instead was issued to actor Ron Howard. The child star had hoped to start his directing career soon, but he accepted a part on the show for one huge asset: if he was hired to play a part on a TV show, he would be able to avoid the Vietnam draft. He was happy to avoid shipping out, Garry Marshall was happy to have him as Richie, but others weren't so keen on the cast list...