On those rare occasions when insurance executive Tara Guizot wears a suit to her Los Angeles office, "people invariably ask me if I'm interviewing for a new job," she said. The trend toward casual dress has gone so far that Matt Smith, a 27-year-old Los Angeles lawyer, is on a quest to establish "Tie Tuesday." He would like to wear a suit to work but knows he'd be ridiculed. Instead, Smith dons a tie every Tuesday and hopes other men in his office will follow. So far, a couple have. "It's just something fun," he said. Forget casual Fridays. In...