Never
argue with a
fool.
People might not be able to tell the
difference.
If you absolutely must, keep as
serene as is possible. Do
not let them
provoke you. Ever. Being really, really, really
sarcastic in a calm tone of
voice is a good way. See
The Matrix.
Remember when
Neo fights the agent
with one hand? Look like that. Let them get worked up. Have fun.