One of the very few people that seem to do exactly what they feel like without concern for Japanese social obligation, are the Yakuza. If you put more than one Japanese in a room, it seems to create a social expectancy - each Japanese watches the other Japanese, to make sure that they don't accidentally do something considered unbecoming for a Japanese. This effect seems to multiply the more people are around. There are only a few people who don't give a shit about this omnipotent social pressure - crazy people, foreigners, and Yakuza.
Social pressure is not as bad here in the U.S.A., but it certainly exists. This is a nice description of how powerful it can be. How much it can suppress people and make them all the same.