The easiest time to be funny is during a fairly serious situation. That way, you can break the ice. It's crazy, but even at funerals, people will get huge laughs.
Everyone is sort of in their own little area counting lines and no one talks when film's not rolling. There's constantly actors coming to me back behind the monitor screaming at me, "Why did my line count drop?" It's a nasty tense environment.
Hollywood has to appeal to the broadest audience, and when it comes to most social and economic issues, America is progressive. Because of that, the messages that are in Hollywood movies tend to be, for instance, pro-environment.