How can you represent criminals?

An interesting post here at Ernie the Attorney on "Musings on our criminal justice system" reminded me of the common experience that criminal defense lawyers have, of running into persons who always seem to wonder what went wrong with us that we ended up representing "criminals." Of course, when their son is busted, or the husband is charged with some fraud, they all receive a bit of shock therapy and commence to open their eyes to the "injustices" of the criminal justice "system" (in their case) and the importance of having a defense lawyer to fight the government every inch of the way. After all, they are not like those criminals I represent, and what they did should not be punished as if they were a criminal. "I didn't kill anyone." Right!