Play it safe. Follow the rules. Respect authority. And, above all, don't stick out like that silly proverbial nail.
That's Japan's recipe for social harmony. Student, salaryman, office lady, homemaker — everyone has a role to play in society, so just fit into the mold and get with the program, OK?
But Japan also has some truly dedicated eccentrics who like to stir things up and add a little spice to life. You can see the really obvious ones on the street: the ojiisan dressed as a schoolgirl, the guy who takes his pet African giant tortoise for a walk or the "tiger man" of Shinjuku careening through the streets on his bicycle.