Refrain from following the example of those whose craving is for attention, not their own improvement, by doing certain things which are calculated to give rise to comment on your appearance or way of living generally.
Avoid shabby attire, long hair, an unkempt beard, an outspoken dislike of silverware, sleeping on the ground and all other misguided means of self-advertisement. The very name of philosophy, however modest the manner in which it is pursued, is unpopular enough as it is: imagine what the reaction would be if we started dissociating ourselves from the conventions of society.
Inwardly everything should be different but our outward face should conform with the crowd… Otherwise we shall repel and alienate the very people whose reform we desire; we shall make them, moreover, reluctant to imitate us in anything for fear they may have to imitate us in everything.
— Seneca, Letter V