I just saw MIBII and was also disspointed. Nobody laughed at any of Johnny Knoxville's attempts at humor. Will Smith's character was kinda lame this time around and it just didn't compare to the first one. That whole thing with Zed was just embarrassing.
I almost fell out of my chair laughing when agent 'M' showed up in the movie. If anyone's planning on renting/seeing it, I won't tell you but it was a rare moment of genius.