Each new generation feels the need to question the shibboleths, values, and assumptions of the generation that preceded it. This was especially true for me and for well-educated others who came of age in the 1960's. Now, after forty years of experience and thought, I have learned to appreciate much of the wisdom of earlier generations.
The value my generation questioned most is the importance of maintaining appearances. To us, what mattered was not the clothes you wore, the car you drove, or the house you lived in, but who you were inside. If externalities were not important, why waste time and energy on them? We proudly wore tattered clothes and hitchhiked or drove small cars.
What I have discovered over the past forty years is that keeping up appearances is important because it is not easy; it shows you care enough about something that you are willing to exert yourself. If you mow your lawn, make your bed, and brush your teeth, you are probably the kind of person who has the energy and willpower to do other things that require effort. Naturalists have come up with similar reasoning for why peacocks sport such cumbersomely large tails. Instinctively, peahens "know" that only a healthy peacock can grow and maintain a large, showy tail. If hens mate with healthy peacocks, they are more likely to give birth to healthy chicks, so peafowl have evolved to grow and appreciate showy tails.
Of course, just because someone lets his lawn grow shaggy doesn't prove that he is careless about other things, or is too disorganized to be effective in other areas. Nor does a mowed lawn prove someone cares about anything else, or is effective in other endeavors. Yet experience suggests that people almost always signal the extent of their caring and effectiveness through their appearance and the appearance of their property, so that appearances are in fact a good indication of someone's substance.
Visible indications of virtue can vary in specifics, depending on the culture an individual endorses. Long hair in a man doesn't necessarily mean he is lazy about grooming; it may simply be his way of signaling his membership in a particular group. Still, if it is tangled and dirty, his character is suspect. Whether his hair is that way intentionally or by neglect, its appearance is meaningful, and offers important insights into the man himself.
Appearances go beyond grooming, clothing, and the condition of one's property appearances include anything about a person that can be readily seen, heard, or smelled. The way a person talks is so important that it could be argued that blacks are more discriminated against for the way they talk than for the color of their skin. In fact, when assessing a person one has just met (something everyone does, consciously or unconsciously), it is much easier to overlook that person's unchangeable characteristics than to overlook appearance characteristics that can be changed. It is wrong to judge a man by his skin color, but the way he talks is under his control, and is fair grist for the mill. Of course, there remains the question of whether a man's accents and word choices simply indicate the group he was born into, or are instead a matter of personal choice. Or does he speak that way because he chooses to associate with people who speak that way? Most people would say a man's way of speaking is a matter of personal choice.