The “Knock, knock” joke was actually very effective, and it worked on many levels. Its main purpose was to erase the effect of the prosecution’s opening statement. It worked.
After the joke, the jurors were like blank pages, as if the prosecution’s emotional opening statement had never happened, and they were ready to take notes on what Don West had to say. And they took notes.
Also, the joke conveyed the idea that the jurors had a lot more to learn about the case, because they really had not heard the abundant evidence that supported the Zimmerman defense.
I know there were many folks here who had an absolute hissy fit over that joke. Lots of stupid statements like “Z shoudl fire his entire defense team NOW.”
As it turns out, whether or not that opening was a gem, their overall defense strategy was excellent. It’s pretty tough to second-guess any single piece of it since it all worked fine together.
As a joke it was terminally dumb. As a ploy to focus the jurors on what the situation actually was right at the beginning it was brilliant. I saw it later in the trial as having pretty much pre-empted most of the prosecution’s arguments.