Who's on first? What's on second?

Where does Language and typical human behavior fail us in Much Ado? Note a specific scene or two where the characters fail to understand each other.  What is the cause or result of this misunderstanding?  With these examples in mind, what is Shakespeare noting about human nature and the facility of language?

The James Dean of his day

Shakespeare was a rebel, a mover and shaker, and an instigator who enjoyed turning convention on its ear.  With this in mind, what typical conventions does he introduce and fiddle with in Much Ado?  Consider stock characters, social rank and status, gender roles, marriage, love, cultural fears and taboos, and even the comic structure itself.

Contrasts meant to lift an eyebrow or two. . . .

What contrasting images and ideas (or elements, including character) do you see at work in Much Ado?  And because we can't possibly leave our understanding at the doorstep of mere observation, What SIGNIFICANCE do these contrasting images serve?