Between shooting. On my street corner where part of the movie was shot in SF an ugly, hair matted little dog comes up to Steve and he reaches down to pet it's head. As soon as he did that the dog fell over on it's side, tongue hanging out the side of it's mouth, and acted dead for a few seconds. All the huge production crews along with Steve cracked up. The dog was alone, no one have given it a command.
Bullitt was the FIRST great chase scene. People in the movie audience wjould actually lean when the cars went around the corners. McQueen actually hit a neighbors car so in the movie, watch the small dent appear in a scene after that bump.