Cary Grant

 One of the things that bothered Cary Grant about filmmaking was how some directors, in an effort to display their authority, would bully actors on the set for the smallest of transgressions. When he became a major leading man, he was essentially bulletproof himself from such pettiness (particularly when he also began producing his films, and thus was the direct boss of his directors). But that meant that some directors would then double down on their anger aimed at lesser cast members.

So Grant developed a little trick to try and help his fellow actors and spare them from directorial wrath: if an actor flubbed a line, Cary would immediately call out for his own next line, claiming he had forgotten it. The director could hardly berate the other actor while not likewise doing the same with his leading man, so he would have no choice but to bite his tongue and calmly call for another take.

According to many who worked with him over the years, this was just one of many small courtesies Cary Grant would routinely show them on the set.